diff --git a/001-hello-world/hello-world.go b/001-hello-world/hello-world.go
index 68a7062..422aa97 100644
--- a/001-hello-world/hello-world.go
+++ b/001-hello-world/hello-world.go
@@ -1,11 +1,11 @@
 // ## Hello World
 
 // Here's an example Go program.
-package main                
+package main
 
 import "fmt"
 
 // It prints `Hello world`.
 func main() {
-    fmt.Println("Hello world")  
+    fmt.Println("Hello world")
 }
diff --git a/002-values/values.go b/002-values/values.go
index 0010a3a..57339cd 100644
--- a/002-values/values.go
+++ b/002-values/values.go
@@ -2,22 +2,22 @@
 
 // Go has various value types, including strings,
 // different types of numbers, booleans, etc.
-package main                           
+package main
 
 import "fmt"
 
 func main() {
 
     // Here are some strings, which can be added together.
-    fmt.Println("Hello world")         
+    fmt.Println("Hello world")
     fmt.Println("Hello " + "other")
 
     // Some examples of integers and floats.
-    fmt.Println("1+1 =", 1+1)          
+    fmt.Println("1+1 =", 1+1)
     fmt.Println("7.0/3.0 =", 7.0/3.0)
 
     // And booleans, which work as you'd expect.
-    fmt.Println(true && false)         
+    fmt.Println(true && false)
     fmt.Println(true || false)
     fmt.Println(!true)
 }
diff --git a/003-variables/variables.go b/003-variables/variables.go
index 0a74ce5..f684dea 100644
--- a/003-variables/variables.go
+++ b/003-variables/variables.go
@@ -7,10 +7,10 @@ import "fmt"
 func main() {
     // `var` declares 1 or more variables. The type comes
     // at the end.
-    var x string = "Hello world"  
-    fmt.Println(x)               
+    var x string = "Hello world"
+    fmt.Println(x)
 
     // An example of declaring multiple `int` variables.
-    var a, b int = 1, 2          
+    var a, b int = 1, 2
     fmt.Println(a, b)
 }
diff --git a/004-inline-assignment/inline-assignment.go b/004-inline-assignment/inline-assignment.go
index 2fa6ac1..533d682 100644
--- a/004-inline-assignment/inline-assignment.go
+++ b/004-inline-assignment/inline-assignment.go
@@ -6,6 +6,6 @@ import "fmt"
 
 func main() {
     // `x := val` is shorthand for `var x type = val`.
-	x := "Hello assignment"  
-	fmt.Println(x)
+    x := "Hello assignment"
+    fmt.Println(x)
 }
diff --git a/009-arrays/arrays.go b/009-arrays/arrays.go
index e4834e7..947db5f 100644
--- a/009-arrays/arrays.go
+++ b/009-arrays/arrays.go
@@ -5,8 +5,8 @@ package main
 import "fmt"
 
 func main() {
-	var x [5]int
-	x[4] = 100
-	fmt.Println(x)
-	fmt.Println(x[4])
+    var x [5]int
+    x[4] = 100
+    fmt.Println(x)
+    fmt.Println(x[4])
 }
diff --git a/010-range/range.go b/010-range/range.go
index e0cba41..1063513 100644
--- a/010-range/range.go
+++ b/010-range/range.go
@@ -11,7 +11,7 @@ func main() {
     x[2] = 77
     x[3] = 82
     x[4] = 83
-    
+
     var total float64 = 0
     for _, value := range x {
         total += value
diff --git a/011-slices/slices.go b/011-slices/slices.go
index 6f4c3db..6d9265c 100644
--- a/011-slices/slices.go
+++ b/011-slices/slices.go
@@ -5,12 +5,12 @@ package main
 import "fmt"
 
 func main() {
-    slice1 := []int{1,2,3}
+    slice1 := []int{1, 2, 3}
     slice2 := append(slice1, 4, 5)
     fmt.Println(slice1)
-	fmt.Println(slice2)
-	slice3 := make([]int, 2)
-	copy(slice3, slice1)
-	fmt.Println(slice1)
-	fmt.Println(slice3)
+    fmt.Println(slice2)
+    slice3 := make([]int, 2)
+    copy(slice3, slice1)
+    fmt.Println(slice1)
+    fmt.Println(slice3)
 }
diff --git a/012-maps/maps.go b/012-maps/maps.go
index a2ac1f7..cd898a2 100644
--- a/012-maps/maps.go
+++ b/012-maps/maps.go
@@ -5,16 +5,16 @@ package main
 import "fmt"
 
 func main() {
-	x := make(map[string]int)
-	x["this"] = 7
-	x["that"] = 13
-	fmt.Println(x)
-	fmt.Println(x["this"])
-	fmt.Println(x["missing"])
-	fmt.Println(len(x))
-	delete(x, "that")
-	fmt.Println(x["that"])
-	fmt.Println(len(x))
-	_, present := x["that"]
-	fmt.Println(present)
+    x := make(map[string]int)
+    x["this"] = 7
+    x["that"] = 13
+    fmt.Println(x)
+    fmt.Println(x["this"])
+    fmt.Println(x["missing"])
+    fmt.Println(len(x))
+    delete(x, "that")
+    fmt.Println(x["that"])
+    fmt.Println(len(x))
+    _, present := x["that"]
+    fmt.Println(present)
 }
diff --git a/013-functions/functions.go b/013-functions/functions.go
index 76dab86..4c793b1 100644
--- a/013-functions/functions.go
+++ b/013-functions/functions.go
@@ -5,16 +5,16 @@ package main
 import "fmt"
 
 func avg(vals []float64) float64 {
-	total := 0.0
-	for _, val := range vals {
-		total += val
-	}
-	return total / float64(len(vals))
+    total := 0.0
+    for _, val := range vals {
+        total += val
+    }
+    return total / float64(len(vals))
 }
 
 func main() {
-	input := []float64{98,93,77,82,83}
-	fmt.Println(input)
-	output := avg(input)
-	fmt.Println(output)
+    input := []float64{98, 93, 77, 82, 83}
+    fmt.Println(input)
+    output := avg(input)
+    fmt.Println(output)
 }
diff --git a/014-multiple-return-values/multiple-returns-values.go b/014-multiple-return-values/multiple-returns-values.go
index 0096bb5..b01f2d6 100644
--- a/014-multiple-return-values/multiple-returns-values.go
+++ b/014-multiple-return-values/multiple-returns-values.go
@@ -10,15 +10,15 @@ import "fmt"
 
 // The `(int, int)` in this signature shows that the
 // function returns 2 ints.
-func vals() (int, int) {  
-    return 3, 7           
-    
+func vals() (int, int) {
+    return 3, 7
+
 }
 
 func main() {
     // Use the 2 different return values from the call,
     // i.e. multiple assignement.
-    x, y := vals()        
+    x, y := vals()
     fmt.Println(x)
     fmt.Println(y)
 }
diff --git a/015-varadic-functions/varadic-functions.go b/015-varadic-functions/varadic-functions.go
index 69fefb7..e472abb 100644
--- a/015-varadic-functions/varadic-functions.go
+++ b/015-varadic-functions/varadic-functions.go
@@ -5,29 +5,29 @@
 // number of arguments that will be needed for a function
 // ahead of time.
 
-package main                   
-                               
+package main
+
 import "fmt"
 
 // Varadic args are declared with `...type` and
 // passed in as a slice.
-func add(nums ...int) int {    
-    fmt.Print(nums, " ")       
+func add(nums ...int) int {
+    fmt.Print(nums, " ")
     total := 0
-    for _, num := range nums {        
-        total += num                
+    for _, num := range nums {
+        total += num
     }
-    return total                    
-}                                   
-                                    
+    return total
+}
+
 func main() {
     // Varadic functions can be called in the usual way.
-    fmt.Println(add(1, 2))     
-    fmt.Println(add(1, 2, 3))    
+    fmt.Println(add(1, 2))
+    fmt.Println(add(1, 2, 3))
 
     // If you already have multiple args in a slice,
     // apply them to a varadic function using `
     // func(slice...)`.                              
-    nums := []int{1, 2, 3, 4}  
-    fmt.Println(add(nums...))  
-}                              
+    nums := []int{1, 2, 3, 4}
+    fmt.Println(add(nums...))
+}
diff --git a/017-recursion/recursion.go b/017-recursion/recursion.go
index f55c4d2..b0a0993 100644
--- a/017-recursion/recursion.go
+++ b/017-recursion/recursion.go
@@ -12,5 +12,5 @@ func factorial(x uint) uint {
 }
 
 func main() {
-	fmt.Println(factorial(7))
+    fmt.Println(factorial(7))
 }
diff --git a/019-panic/panic.go b/019-panic/panic.go
index 6bf9e72..5b66167 100644
--- a/019-panic/panic.go
+++ b/019-panic/panic.go
@@ -9,5 +9,5 @@ func main() {
     // We'll use panic throught this book to check for
     // unexpected errors. This is the only program in the
     // book designed to panic.
-	panic("O noes")  
-}	                 
+    panic("O noes")
+}
diff --git a/021-new/new.go b/021-new/new.go
index 4c98b62..59385bd 100644
--- a/021-new/new.go
+++ b/021-new/new.go
@@ -9,8 +9,8 @@ func one(xPtr *int) {
 }
 func main() {
     xPtr := new(int)
-	fmt.Println(xPtr)
-	fmt.Println(*xPtr)
+    fmt.Println(xPtr)
+    fmt.Println(*xPtr)
     one(xPtr)
     fmt.Println(xPtr)
     fmt.Println(*xPtr)
diff --git a/022-structs/structs.go b/022-structs/structs.go
index 449860a..bd28bfb 100644
--- a/022-structs/structs.go
+++ b/022-structs/structs.go
@@ -9,16 +9,16 @@ type Circle struct {
 }
 
 func main() {
-	cEmptyPtr := new(Circle)
-	fmt.Println(cEmptyPtr)
-	fmt.Println(*cEmptyPtr)
-	
-	cValue := Circle{x: 1, y: 2, r: 5}
-	fmt.Println(&cValue)
-	fmt.Println(cValue)
+    cEmptyPtr := new(Circle)
+    fmt.Println(cEmptyPtr)
+    fmt.Println(*cEmptyPtr)
 
-	cOrdered := Circle{1, 2, 5}
-	fmt.Println(cOrdered)
+    cValue := Circle{x: 1, y: 2, r: 5}
+    fmt.Println(&cValue)
+    fmt.Println(cValue)
+
+    cOrdered := Circle{1, 2, 5}
+    fmt.Println(cOrdered)
 }
 
 // todo: add field access
diff --git a/023-methods/methods.go b/023-methods/methods.go
index 196b8a4..8921124 100644
--- a/023-methods/methods.go
+++ b/023-methods/methods.go
@@ -10,7 +10,7 @@ type Circle struct {
 }
 
 func (c *Circle) area() float64 {
-    return math.Pi * c.r*c.r
+    return math.Pi * c.r * c.r
 }
 
 type Rectangle struct {
@@ -30,10 +30,10 @@ func (r *Rectangle) area() float64 {
 }
 
 func main() {
-	circle := Circle{x: 0, y: 3, r: 5}
-	fmt.Println(circle.area())
-	rectangle := Rectangle {x1: 3, x2: 10, y1: 5, y2: 7}
-	fmt.Println(rectangle.area())
+    circle := Circle{x: 0, y: 3, r: 5}
+    fmt.Println(circle.area())
+    rectangle := Rectangle{x1: 3, x2: 10, y1: 5, y2: 7}
+    fmt.Println(rectangle.area())
 }
 
 // todo: pointer vs value receivers
diff --git a/024-embedding/embedding.go b/024-embedding/embedding.go
index c5a1f96..6992bf7 100644
--- a/024-embedding/embedding.go
+++ b/024-embedding/embedding.go
@@ -14,7 +14,7 @@ type Circle struct {
 }
 
 func (c *Circle) area() float64 {
-    return math.Pi * c.r*c.r
+    return math.Pi * c.r * c.r
 }
 
 type Rectangle struct {
@@ -42,14 +42,14 @@ func totalArea(shapes ...Shape) float64 {
 }
 
 func main() {
-	circle := Circle{x: 0, y: 3, r: 5}
-	rectangle := Rectangle {x1: 3, x2: 10, y1: 5, y2: 7}
+    circle := Circle{x: 0, y: 3, r: 5}
+    rectangle := Rectangle{x1: 3, x2: 10, y1: 5, y2: 7}
 
-	area := 0.0
-	for _, s := range []Shape{&circle, &rectangle} {
-		area += s.area()
-	}
-	fmt.Println(area)
+    area := 0.0
+    for _, s := range []Shape{&circle, &rectangle} {
+        area += s.area()
+    }
+    fmt.Println(area)
 }
 
 // todo: is this named wrong?
diff --git a/026-errors/errors.go b/026-errors/errors.go
index b78c3cd..7316902 100644
--- a/026-errors/errors.go
+++ b/026-errors/errors.go
@@ -2,22 +2,25 @@
 
 package main
 
-import ("fmt"; "errors")
+import (
+    "errors"
+    "fmt"
+)
 
 func myFun(arg int) (int, error) {
-	if arg == 42 {
-		return -1, errors.New("Can't work with 42")
-		
-	}
-	return arg + 3, nil
+    if arg == 42 {
+        return -1, errors.New("Can't work with 42")
+
+    }
+    return arg + 3, nil
 }
 
 func main() {
-	r, _ := myFun(7)
-	fmt.Println(r)
+    r, _ := myFun(7)
+    fmt.Println(r)
 
-	_, e := myFun(42)
-	fmt.Println(e)
+    _, e := myFun(42)
+    fmt.Println(e)
 }
 
 // todo: custom errors
diff --git a/027-ok-guards/ok-guards.go b/027-ok-guards/ok-guards.go
index 6e5b577..fc5e540 100644
--- a/027-ok-guards/ok-guards.go
+++ b/027-ok-guards/ok-guards.go
@@ -5,18 +5,18 @@ package main
 import "fmt"
 
 func main() {
-	x := make(map[string]string)
-	x["here"] = "yes"
+    x := make(map[string]string)
+    x["here"] = "yes"
 
-	if name, ok := x["?"]; ok {    
-	    fmt.Println(name)
-	} else {
-		fmt.Println("miss")
-	}
+    if name, ok := x["?"]; ok {
+        fmt.Println(name)
+    } else {
+        fmt.Println("miss")
+    }
 
-	if name, ok := x["here"]; ok {
-	    fmt.Println(name)
-	}
+    if name, ok := x["here"]; ok {
+        fmt.Println(name)
+    }
 }
 
 // todo: note about use with errors
diff --git a/029-concurrent-goroutines/concurrent-goroutines.go b/029-concurrent-goroutines/concurrent-goroutines.go
index 64235fa..28d05a5 100644
--- a/029-concurrent-goroutines/concurrent-goroutines.go
+++ b/029-concurrent-goroutines/concurrent-goroutines.go
@@ -9,18 +9,18 @@ import "fmt"
 func f(n int) {
     for i := 0; i < 10; i++ {
         fmt.Println(n, ":", i)
-		time.Sleep(time.Millisecond * time.Duration(rand.Intn(150)))
+        time.Sleep(time.Millisecond * time.Duration(rand.Intn(150)))
     }
 }
 
 func main() {
     for i := 0; i < 5; i++ {
-		f(i)
-	}
-	fmt.Println()
-	for i := 0; i < 5; i++ {
-		go f(i)
-	}
+        f(i)
+    }
+    fmt.Println()
+    for i := 0; i < 5; i++ {
+        go f(i)
+    }
     var input string
     fmt.Scanln(&input)
 }
diff --git a/030-channels/channels.go b/030-channels/channels.go
index 4c2f135..3af0cd0 100644
--- a/030-channels/channels.go
+++ b/030-channels/channels.go
@@ -6,7 +6,7 @@ import "fmt"
 
 func main() {
     var messages chan string = make(chan string)
-    go func() { messages <- "ping"}()
-	msg := <- messages
-	fmt.Println(msg)
+    go func() { messages <- "ping" }()
+    msg := <-messages
+    fmt.Println(msg)
 }
diff --git a/031-channel-buffering/channel-buffering.go b/031-channel-buffering/channel-buffering.go
index 9126111..98b774b 100644
--- a/031-channel-buffering/channel-buffering.go
+++ b/031-channel-buffering/channel-buffering.go
@@ -7,6 +7,6 @@ import "fmt"
 func main() {
     var messages chan string = make(chan string, 1)
     messages <- "ping"
-	msg := <- messages
-	fmt.Println(msg)
+    msg := <-messages
+    fmt.Println(msg)
 }
diff --git a/032-channel-directions/channel-directions.go b/032-channel-directions/channel-directions.go
index 91e3096..6d336fa 100644
--- a/032-channel-directions/channel-directions.go
+++ b/032-channel-directions/channel-directions.go
@@ -12,14 +12,14 @@ func pinger(pings chan<- string) {
 
 func ponger(pings <-chan string, pongs chan<- string) {
     for {
-	  <- pings
-      pongs <- "pong"
+        <-pings
+        pongs <- "pong"
     }
 }
 
 func printer(pongs <-chan string) {
     for {
-        msg := <- pongs
+        msg := <-pongs
         fmt.Println(msg)
     }
 }
@@ -32,6 +32,6 @@ func main() {
     go ponger(pings, pongs)
     go printer(pongs)
 
-	var input string
+    var input string
     fmt.Scanln(&input)
 }
diff --git a/033-synchronization/synchronization.go b/033-synchronization/synchronization.go
index de17241..c8abb1e 100644
--- a/033-synchronization/synchronization.go
+++ b/033-synchronization/synchronization.go
@@ -4,29 +4,29 @@
 // accross goroutines. Here's an example of waiting
 // for another goroutine to finish.
 
-package main                     
-                                 
-import "fmt"                     
+package main
+
+import "fmt"
 import "time"
 
 // The `done` channel will be used for
 // synchronization.
-func worker(done chan<- bool) {  
-    fmt.Print("Working...")      
+func worker(done chan<- bool) {
+    fmt.Print("Working...")
     time.Sleep(time.Second)
     fmt.Println(" done")
 
     // Send a value to notify that the work is done.
-    done <- true                 
+    done <- true
 }
 
 func main() {
     // Start a worker goroutine, give it the channel to
     // notify on.
-    done := make(chan bool, 1)   
-    go worker(done)              
-    
+    done := make(chan bool, 1)
+    go worker(done)
+
     // Block until we can receive a value from the worker
     // over the channel.
-    <- done                      
-}                                
+    <-done
+}
diff --git a/034-select/select.go b/034-select/select.go
index 5c6398e..0007a65 100644
--- a/034-select/select.go
+++ b/034-select/select.go
@@ -8,27 +8,27 @@ import "fmt"
 func main() {
     c1 := make(chan string)
     c2 := make(chan string)
-	d  := make(chan bool, 1)
+    d := make(chan bool, 1)
 
     go func() {
         time.Sleep(time.Second * 1)
-		c1 <- "from 1"
+        c1 <- "from 1"
     }()
     go func() {
         time.Sleep(time.Second * 2)
-		c2 <- "from 2"
+        c2 <- "from 2"
     }()
 
     go func() {
-        for i :=0; i < 2; i ++ {
+        for i := 0; i < 2; i++ {
             select {
-            case msg1 := <- c1:
+            case msg1 := <-c1:
                 fmt.Println(msg1)
-            case msg2 := <- c2:
+            case msg2 := <-c2:
                 fmt.Println(msg2)
             }
         }
-		d <- true
+        d <- true
     }()
-	<- d
+    <-d
 }
diff --git a/035-timeouts/timeouts.go b/035-timeouts/timeouts.go
index 8c5f43e..5733d32 100644
--- a/035-timeouts/timeouts.go
+++ b/035-timeouts/timeouts.go
@@ -7,21 +7,21 @@ import "fmt"
 
 func main() {
     c := make(chan string)
-	d := make(chan bool, 1)
+    d := make(chan bool, 1)
 
     go func() {
         time.Sleep(time.Millisecond * 1500)
-		c <- "ready"
+        c <- "ready"
     }()
 
     go func() {
-      select {
-      case msg := <- c:
-          fmt.Println(msg)
-      case <- time.After(time.Millisecond * 1000):
-           fmt.Println("timeout")
-       }
-	   d <- true
-    }()		
-	<- d
+        select {
+        case msg := <-c:
+            fmt.Println(msg)
+        case <-time.After(time.Millisecond * 1000):
+            fmt.Println("timeout")
+        }
+        d <- true
+    }()
+    <-d
 }
diff --git a/036-scatter-gather/081-scatter-gather.go b/036-scatter-gather/081-scatter-gather.go
index fc0c3a9..6b814d8 100644
--- a/036-scatter-gather/081-scatter-gather.go
+++ b/036-scatter-gather/081-scatter-gather.go
@@ -8,19 +8,19 @@ import "math/rand"
 import "fmt"
 
 func main() {
-	times := new([20]int)
-	wait := new(sync.WaitGroup)
-	for i := 0; i < 20; i++ {
-		n := i
-	  	wait.Add(1)
-	  	go func() {
-	  	  	opTime := rand.Intn(2000)
-	  	  	time.Sleep(time.Duration(opTime) * time.Millisecond)
-	  	  	fmt.Println(n)
-	  	  	times[n] = opTime
-	  	  	wait.Done()
-	  	}()
-	}
-	wait.Wait()
-	fmt.Println(*times)
+    times := new([20]int)
+    wait := new(sync.WaitGroup)
+    for i := 0; i < 20; i++ {
+        n := i
+        wait.Add(1)
+        go func() {
+            opTime := rand.Intn(2000)
+            time.Sleep(time.Duration(opTime) * time.Millisecond)
+            fmt.Println(n)
+            times[n] = opTime
+            wait.Done()
+        }()
+    }
+    wait.Wait()
+    fmt.Println(*times)
 }
diff --git a/037-rate-limiting/rate-limiting.go b/037-rate-limiting/rate-limiting.go
index c8d1879..5ffd5ab 100644
--- a/037-rate-limiting/rate-limiting.go
+++ b/037-rate-limiting/rate-limiting.go
@@ -5,10 +5,10 @@ import "time"
 import "fmt"
 
 func main() {
-	throttle := time.Tick(time.Millisecond * 200)
-	for {
-  		<- throttle
-  		go fmt.Println("rate-limited action")
+    throttle := time.Tick(time.Millisecond * 200)
+    for {
+        <-throttle
+        go fmt.Println("rate-limited action")
     }
 }
 
diff --git a/039-timers/timers.go b/039-timers/timers.go
index 536a5a3..b5e3169 100644
--- a/039-timers/timers.go
+++ b/039-timers/timers.go
@@ -6,17 +6,17 @@ import "time"
 import "fmt"
 
 func main() {
-	timer1 := time.NewTimer(time.Second)
-	<- timer1.C
-	fmt.Println("Timer 1 expired")
-	stop1 := timer1.Stop()
-	fmt.Println("Timer 2 stopped:", stop1)
+    timer1 := time.NewTimer(time.Second)
+    <-timer1.C
+    fmt.Println("Timer 1 expired")
+    stop1 := timer1.Stop()
+    fmt.Println("Timer 2 stopped:", stop1)
 
-	timer2 := time.NewTimer(time.Second)
-	go func() {
-		<- timer2.C
-		fmt.Println("Timer 2 expired")
-	}()
-	stop2 := timer2.Stop()
-	fmt.Println("Timer 2 stopped:", stop2)
+    timer2 := time.NewTimer(time.Second)
+    go func() {
+        <-timer2.C
+        fmt.Println("Timer 2 expired")
+    }()
+    stop2 := timer2.Stop()
+    fmt.Println("Timer 2 stopped:", stop2)
 }
diff --git a/041-sorting/sorting.go b/041-sorting/sorting.go
index 98d3085..b3b766c 100644
--- a/041-sorting/sorting.go
+++ b/041-sorting/sorting.go
@@ -3,25 +3,25 @@
 // The `sort` package implements sorting for builtins
 // and user-defined types. We'll look at some of the
 // sorts for builtins here.
-package main                         
-                                     
-import "fmt"                         
+package main
+
+import "fmt"
 import "sort"
 
 func main() {
     // Sort methods are specific to the builtin type.
     // Sorting is in-place (doesn't return a new slice).
-	strs := []string{"c", "a", "b"}
-	sort.Strings(strs)               
-	fmt.Println(strs)                
+    strs := []string{"c", "a", "b"}
+    sort.Strings(strs)
+    fmt.Println(strs)
 
     // Sorting methods are named after the type.
     ints := []int{7, 2, 4}
-    sort.Ints(ints)                  
+    sort.Ints(ints)
     fmt.Println(ints)
 
     // Check if a slice is in sorted order.
-    s := sort.IntsAreSorted(ints)    
+    s := sort.IntsAreSorted(ints)
     fmt.Println(s)
 }
 
diff --git a/042-sorting-by-functions/sorting-by-functions.go b/042-sorting-by-functions/sorting-by-functions.go
index 4c8c317..734327d 100644
--- a/042-sorting-by-functions/sorting-by-functions.go
+++ b/042-sorting-by-functions/sorting-by-functions.go
@@ -2,14 +2,18 @@
 
 package main
 
-import ("fmt" ; "sort")
+import (
+    "fmt"
+    "sort"
+)
 
-type Person struct { 
+type Person struct {
     Name string
-    Age int
+    Age  int
 }
 
 type ByName []Person
+
 func (this ByName) Len() int {
     return len(this)
 }
@@ -21,8 +25,9 @@ func (this ByName) Swap(i, j int) {
 }
 
 type ByAge []Person
+
 func (this ByAge) Len() int {
-	return len(this)
+    return len(this)
 }
 func (this ByAge) Less(i, j int) bool {
     return this[i].Age < this[j].Age
@@ -33,15 +38,15 @@ func (this ByAge) Swap(i, j int) {
 
 func main() {
     kids := []Person{
-		{"Jack", 10},
+        {"Jack", 10},
         {"Jill", 9},
-        {"Bob",  12},
+        {"Bob", 12},
     }
     fmt.Println("Original:", kids)
-	
-	sort.Sort(ByName(kids))
-	fmt.Println("ByName:  ", kids)
 
-	sort.Sort(ByAge(kids))
-	fmt.Println("ByAge:   ", kids)
+    sort.Sort(ByName(kids))
+    fmt.Println("ByName:  ", kids)
+
+    sort.Sort(ByAge(kids))
+    fmt.Println("ByAge:   ", kids)
 }
diff --git a/043-collection-functions/collection-functions.go b/043-collection-functions/collection-functions.go
index 20cb9e6..662ff19 100644
--- a/043-collection-functions/collection-functions.go
+++ b/043-collection-functions/collection-functions.go
@@ -1,95 +1,95 @@
 // ## Collection Functions
 
-package main            
+package main
 
 import "strings"
 import "fmt"
 
 func Index(elems []string, val string) int {
-	for i, v := range elems {
-		if v == val {
-			return i
-		}
-	}
-	return -1
+    for i, v := range elems {
+        if v == val {
+            return i
+        }
+    }
+    return -1
 }
 
 func Include(elems []string, val string) bool {
-	return Index(elems, val) >= 0
+    return Index(elems, val) >= 0
 }
 
-func Any(elems []string, f func(string)bool) bool {
-	for _, v := range elems {
-		if f(v) {
-			return true
-		}
-	}
-	return false
+func Any(elems []string, f func(string) bool) bool {
+    for _, v := range elems {
+        if f(v) {
+            return true
+        }
+    }
+    return false
 }
 
-func All(elems []string, f func(string)bool) bool {
-	for _, v := range elems {
-		if !f(v) {
-			return false
-		}
-	}
-	return true
+func All(elems []string, f func(string) bool) bool {
+    for _, v := range elems {
+        if !f(v) {
+            return false
+        }
+    }
+    return true
 }
 
-func Filter(elems []string, f func(string)bool) []string {
-	filtered := []string{}
-	for _, v := range elems {
-		if f(v) {
-			filtered = append(filtered, v)
-		}
-	}
-	return filtered
+func Filter(elems []string, f func(string) bool) []string {
+    filtered := []string{}
+    for _, v := range elems {
+        if f(v) {
+            filtered = append(filtered, v)
+        }
+    }
+    return filtered
 }
 
-func Map(elems []string, f func(string)string) []string {
-	mapped := make([]string, len(elems))
-	for i, v := range elems {
-		mapped[i] = f(v)
-	}
-	return mapped
+func Map(elems []string, f func(string) string) []string {
+    mapped := make([]string, len(elems))
+    for i, v := range elems {
+        mapped[i] = f(v)
+    }
+    return mapped
 }
 
 func main() {
-	var elems = []string{"peach", "apple", "pear", "banana"}
+    var elems = []string{"peach", "apple", "pear", "banana"}
 
-	fmt.Println(Index(elems, "pear"))
-	fmt.Println(Index(elems, "grape"))
-	fmt.Println()
+    fmt.Println(Index(elems, "pear"))
+    fmt.Println(Index(elems, "grape"))
+    fmt.Println()
 
-	fmt.Println(Include(elems, "pear"))
-	fmt.Println(Include(elems, "grape"))
-	fmt.Println()
+    fmt.Println(Include(elems, "pear"))
+    fmt.Println(Include(elems, "grape"))
+    fmt.Println()
 
-	fmt.Println(Any(elems, func(v string) bool {
-		return strings.HasPrefix(v, "p")
-	}))
-	fmt.Println(Any(elems, func(v string) bool {
-		return strings.HasPrefix(v, "g")
-	}))
-	fmt.Println()
+    fmt.Println(Any(elems, func(v string) bool {
+        return strings.HasPrefix(v, "p")
+    }))
+    fmt.Println(Any(elems, func(v string) bool {
+        return strings.HasPrefix(v, "g")
+    }))
+    fmt.Println()
 
-	fmt.Println(All(elems, func(v string) bool {
-		return strings.Contains(v, "a")
-	}))
-	fmt.Println(All(elems, func(v string) bool {
-		return strings.Contains(v, "p")
-	}))
-	fmt.Println()
+    fmt.Println(All(elems, func(v string) bool {
+        return strings.Contains(v, "a")
+    }))
+    fmt.Println(All(elems, func(v string) bool {
+        return strings.Contains(v, "p")
+    }))
+    fmt.Println()
 
-	fmt.Println(Filter(elems, func(v string) bool {
-		return strings.Contains(v, "p")
-	}))
-	fmt.Println()
-	
-	fmt.Println(Map(elems, func(s string) string {
-		return strings.ToUpper(s)
-	}))
-	fmt.Println()
+    fmt.Println(Filter(elems, func(v string) bool {
+        return strings.Contains(v, "p")
+    }))
+    fmt.Println()
+
+    fmt.Println(Map(elems, func(s string) string {
+        return strings.ToUpper(s)
+    }))
+    fmt.Println()
 }
 
 // todo: generics
diff --git a/044-string-functions/string-functions.go b/044-string-functions/string-functions.go
index 15e67de..c9dd0b0 100644
--- a/044-string-functions/string-functions.go
+++ b/044-string-functions/string-functions.go
@@ -6,7 +6,7 @@ import "strings"
 import "fm"
 
 func p(o interface{}) {
-	fmt.Println(o)
+    fmt.Println(o)
 }
 
 func main() {
@@ -15,8 +15,8 @@ func main() {
     p(strings.Count("test", "t"))
     p(strings.HasPrefix("test", "te"))
     p(strings.HasSuffix("test", "st"))
-	p(strings.Index("test", "e"))
-    p(strings.Join([]string{"a","b"}, "-"))
+    p(strings.Index("test", "e"))
+    p(strings.Join([]string{"a", "b"}, "-"))
     p(strings.Repeat("a", 5))
     p(strings.Replace("foo", "o", "0", -1))
     p(strings.Replace("foo", "o", "0", 1))
diff --git a/046-regexs/regexs.go b/046-regexs/regexs.go
index 0e2bfd7..29c014b 100644
--- a/046-regexs/regexs.go
+++ b/046-regexs/regexs.go
@@ -6,14 +6,14 @@ import "regexp"
 import "fmt"
 
 func main() {
-	m1, _ := regexp.MatchString("p[a-z]+ch", "apple")
-	m2, _ := regexp.MatchString("p[a-z]+ch", "peach")
-	fmt.Println(m1)
-	fmt.Println(m2)
+    m1, _ := regexp.MatchString("p[a-z]+ch", "apple")
+    m2, _ := regexp.MatchString("p[a-z]+ch", "peach")
+    fmt.Println(m1)
+    fmt.Println(m2)
 
-	r1, _ := regexp.Compile("p[a-z]+ch")
-	fmt.Println(r1.MatchString("apple"))
-	fmt.Println(r1.MatchString("peach"))
+    r1, _ := regexp.Compile("p[a-z]+ch")
+    fmt.Println(r1.MatchString("apple"))
+    fmt.Println(r1.MatchString("peach"))
 }
 
 // todo: more
diff --git a/047-bytes/bytes.go b/047-bytes/bytes.go
index 3eab9a2..5e337e9 100644
--- a/047-bytes/bytes.go
+++ b/047-bytes/bytes.go
@@ -5,8 +5,8 @@ package main
 import "fmt"
 
 func main() {
-	arr := []byte("some bytes")
-	str := string([]byte{'a', ' ', 's', 't', 'r', 'i', 'n', 'g'})
-	fmt.Println(arr)
-	fmt.Println(str)
+    arr := []byte("some bytes")
+    str := string([]byte{'a', ' ', 's', 't', 'r', 'i', 'n', 'g'})
+    fmt.Println(arr)
+    fmt.Println(str)
 }
diff --git a/048-json/json.go b/048-json/json.go
index 927aaf9..1cdf6d7 100644
--- a/048-json/json.go
+++ b/048-json/json.go
@@ -6,32 +6,34 @@ import "encoding/json"
 import "fmt"
 
 func main() {
-	// data to bytes/string
-	bol, _ := json.Marshal(true)
-	fmt.Println(string(bol))
+    // data to bytes/string
+    bol, _ := json.Marshal(true)
+    fmt.Println(string(bol))
 
-	num, _ := json.Marshal(1)
-	fmt.Println(string(num))
+    num, _ := json.Marshal(1)
+    fmt.Println(string(num))
 
-	str, _ := json.Marshal("gopher")
-	fmt.Println(string(str))
-	
-	arr, _ := json.Marshal([]string{"apple", "peach", "pear"})
-	fmt.Println(string(arr))
+    str, _ := json.Marshal("gopher")
+    fmt.Println(string(str))
 
-	hsh, _ := json.Marshal(map[string]int{"apple": 5, "lettuce": 7})
-	fmt.Println(string(hsh))
+    arr, _ := json.Marshal([]string{"apple", "peach", "pear"})
+    fmt.Println(string(arr))
 
-	// string to data
-	byt := []byte(`{"Name":"Wednesday","Age":6,"Parents":["Gomez","Morticia"]}`)
-	var dat map[string]interface{}
-	err := json.Unmarshal(byt, &dat)
-	if err != nil { panic(err) }
-	fmt.Println(dat)
+    hsh, _ := json.Marshal(map[string]int{"apple": 5, "lettuce": 7})
+    fmt.Println(string(hsh))
 
-	name := dat["Name"].(string)
-	fmt.Println(name)
+    // string to data
+    byt := []byte(`{"Name":"Wednesday","Age":6,"Parents":["Gomez","Morticia"]}`)
+    var dat map[string]interface{}
+    err := json.Unmarshal(byt, &dat)
+    if err != nil {
+        panic(err)
+    }
+    fmt.Println(dat)
 
-	parents := dat["Parents"].([]interface{})
-	fmt.Println(parents)
+    name := dat["Name"].(string)
+    fmt.Println(name)
+
+    parents := dat["Parents"].([]interface{})
+    fmt.Println(parents)
 }
diff --git a/050-epochs/epochs.go b/050-epochs/epochs.go
index c5cad5c..d489859 100644
--- a/050-epochs/epochs.go
+++ b/050-epochs/epochs.go
@@ -1,19 +1,19 @@
 // ## Epochs
 
-package main                    
-                  
+package main
+
 import "time"
 
 func main() {
     // Use `time.Now` with `Unix` or `UnixNane` to get
     // elapsed time since the Unix epoch.
-	now := time.Now()
-	secs := now.Unix()
-	nanos := now.UnixNano()
+    now := time.Now()
+    secs := now.Unix()
+    nanos := now.UnixNano()
 
     // There is no `UnixMillis`.
-	millis := nanos / 1000000
-	println("Secs:  ", secs)
-	println("Millis:", millis)
-	println("Nanos: ", nanos)
+    millis := nanos / 1000000
+    println("Secs:  ", secs)
+    println("Millis:", millis)
+    println("Nanos: ", nanos)
 }
diff --git a/051-elapsed-time/elapsed-time.go b/051-elapsed-time/elapsed-time.go
index 66345a1..ae8026d 100644
--- a/051-elapsed-time/elapsed-time.go
+++ b/051-elapsed-time/elapsed-time.go
@@ -6,7 +6,7 @@ import "time"
 import "fmt"
 
 func main() {
-	start := time.Now()
-	time.Sleep(3 * time.Second)
-	fmt.Println(time.Since(start))
+    start := time.Now()
+    time.Sleep(3 * time.Second)
+    fmt.Println(time.Since(start))
 }
diff --git a/052-random-numbers/random-numbers.go b/052-random-numbers/random-numbers.go
index e857c9b..38f6aac 100644
--- a/052-random-numbers/random-numbers.go
+++ b/052-random-numbers/random-numbers.go
@@ -1,7 +1,7 @@
 // Random Numbers
 
-package main                        
-                 
+package main
+
 // The `math/rand` package provides psuedo-random
 // numbers.
 import "math/rand"
@@ -10,30 +10,30 @@ import "fmt"
 func main() {
     // For example, `rand.Intn` returns a random `int` n,
     // `0 <= n < 100`.
-	fmt.Print(rand.Intn(100), ",")  
-	fmt.Print(rand.Intn(100))       
+    fmt.Print(rand.Intn(100), ",")
+    fmt.Print(rand.Intn(100))
     fmt.Println()
 
     // `rand.Float64` returns a `float64` `f`,
     // `0.0 <= f < 1.0`.
-	fmt.Println(rand.Float64())     
-	                                
+    fmt.Println(rand.Float64())
+
     // To make the psuedo-random generator deterministic,
     // give it a well-known seed.                                               
-    s1 := rand.NewSource(42)        
-	r1 := rand.New(s1)              
-											   
-	// Call the resulting `rand.Source` just like the
-	// functions on the `rand` package.
-	fmt.Print(r1.Intn(100), ",")    
-	fmt.Print(r1.Intn(100))         
+    s1 := rand.NewSource(42)
+    r1 := rand.New(s1)
+
+    // Call the resulting `rand.Source` just like the
+    // functions on the `rand` package.
+    fmt.Print(r1.Intn(100), ",")
+    fmt.Print(r1.Intn(100))
     fmt.Println()
 
     // If you seed a source with the same number, it
     // produces the same sequence of random numbers.
-    s2 := rand.NewSource(42)        
-	r2 := rand.New(s2)              
-	fmt.Print(r2.Intn(100), ",")                  
-	fmt.Print(r2.Intn(100))
-	fmt.Println()
+    s2 := rand.NewSource(42)
+    r2 := rand.New(s2)
+    fmt.Print(r2.Intn(100), ",")
+    fmt.Print(r2.Intn(100))
+    fmt.Println()
 }
diff --git a/053-number-parsing/number-parsing.go b/053-number-parsing/number-parsing.go
index de07b4a..bdda3a0 100644
--- a/053-number-parsing/number-parsing.go
+++ b/053-number-parsing/number-parsing.go
@@ -8,23 +8,23 @@ import "fmt"
 
 func main() {
     // `64` tells how many bits of precision to parse.
-    f, _ := strconv.ParseFloat("1.234", 64)    
+    f, _ := strconv.ParseFloat("1.234", 64)
     fmt.Println(f)
-    
+
     // `0` means infer the base from the string.
     // `64` requires that the result fit in 64 bits.
-    i, _ := strconv.ParseInt("123", 0, 64)     
-    println(i)                                 
+    i, _ := strconv.ParseInt("123", 0, 64)
+    println(i)
 
     // `ParseInt` will recognize hex-formatted numbers.
-    d, _ := strconv.ParseInt("0x1b3e", 0, 64)  
+    d, _ := strconv.ParseInt("0x1b3e", 0, 64)
     println(d)
 
     // `Atoi` is a convenienice function for `int` parsing.
-    k, _ := strconv.Atoi("456")                
+    k, _ := strconv.Atoi("456")
     println(k)
 
     // Parse functions return an error on bad input.
-    _, e := strconv.Atoi("wat")                
+    _, e := strconv.Atoi("wat")
     fmt.Println(e)
 }
diff --git a/056-reading-files/reading-files.go b/056-reading-files/reading-files.go
index 720a705..c713019 100644
--- a/056-reading-files/reading-files.go
+++ b/056-reading-files/reading-files.go
@@ -13,5 +13,4 @@ func main() {
     fmt.Print(string(contents))
 }
 
-
 // todo: streaming reads
diff --git a/057-writing-files/writing-files.go b/057-writing-files/writing-files.go
index e1c4d08..58ebd98 100644
--- a/057-writing-files/writing-files.go
+++ b/057-writing-files/writing-files.go
@@ -5,7 +5,7 @@ package main
 import "os"
 
 func main() {
-	file, err := os.Create("xx-file-write.txt")
+    file, err := os.Create("xx-file-write.txt")
     if err != nil {
         panic(err)
     }
diff --git a/059-command-line-arguments/command-line-arguments.go b/059-command-line-arguments/command-line-arguments.go
index c5bfdda..0b0acf8 100644
--- a/059-command-line-arguments/command-line-arguments.go
+++ b/059-command-line-arguments/command-line-arguments.go
@@ -2,25 +2,24 @@
 
 // Use `os.Args` to access command-line arguments and
 // the name of the program.
-package main                        
-                                    
+package main
+
 import "os"
 import "fmt"
 
 func main() {
     // `os.Args` includes the program name as the first
     // value.                                              
-	argsWithProg := os.Args         
-	argsWithoutProg := os.Args[1:]  
+    argsWithProg := os.Args
+    argsWithoutProg := os.Args[1:]
 
     // `Args` are a slice, you can get individual args
     // with normal indexing.
-	arg := os.Args[3]               
-                                    
+    arg := os.Args[3]
 
-	fmt.Println(argsWithProg)       
-	fmt.Println(argsWithoutProg)
-	fmt.Println(arg)
+    fmt.Println(argsWithProg)
+    fmt.Println(argsWithoutProg)
+    fmt.Println(arg)
 }
 
 // todo: discuss building before here
diff --git a/060-command-line-flags/command-line-flags.go b/060-command-line-flags/command-line-flags.go
index 64a8092..89b8b4e 100644
--- a/060-command-line-flags/command-line-flags.go
+++ b/060-command-line-flags/command-line-flags.go
@@ -8,11 +8,11 @@ import "fmt"
 func main() {
     maxp := flag.Int("repeat", 3, "time to repeat args")
     flag.Parse()
-	for i := 0; i < *maxp; i++ {
-		for _, arg := range flag.Args() {
-			fmt.Println(arg)
-		}
-	}
+    for i := 0; i < *maxp; i++ {
+        for _, arg := range flag.Args() {
+            fmt.Println(arg)
+        }
+    }
 }
 
 // todo: multiple flags
diff --git a/061-environment-variables/environment-variables.go b/061-environment-variables/environment-variables.go
index 31ecc64..b8cfff0 100644
--- a/061-environment-variables/environment-variables.go
+++ b/061-environment-variables/environment-variables.go
@@ -1,6 +1,6 @@
 // ## Environment Variables
 
-package main                           
+package main
 
 // Use the `os` package to list, set, and get
 // environment variables.                                                           
@@ -12,15 +12,15 @@ func main() {
     // `os.Environ` returns a slice of strings in the form
     // `KEY=value`. You can `strings.Split` them to get
     // the key and value.
-    for _, e := range os.Environ() {   
-        pair := strings.Split(e, "=")  
-        fmt.Println(pair[0])           
+    for _, e := range os.Environ() {
+        pair := strings.Split(e, "=")
+        fmt.Println(pair[0])
     }
     fmt.Println()
 
     // `Setenv` sets a given key, value pair.
     // `Getenv` returns the value at key, or an empty
     // string if the key isn't present.
-    os.Setenv("FOO", "bar")            
-    fmt.Println(os.Getenv("FOO"))      
-}                                      
+    os.Setenv("FOO", "bar")
+    fmt.Println(os.Getenv("FOO"))
+}
diff --git a/062-spawning-processes/spawning-processes.go b/062-spawning-processes/spawning-processes.go
index e9ea292..44ac4b7 100644
--- a/062-spawning-processes/spawning-processes.go
+++ b/062-spawning-processes/spawning-processes.go
@@ -6,13 +6,13 @@ import "os/exec"
 import "fmt"
 
 func main() {
-	cmd := exec.Command("ls", "-a", "-l")
-	out, err := cmd.Output()
-	if err != nil {
-		panic(err)
-	}
-	fmt.Println("Files:")
-	fmt.Print(string(out))
+    cmd := exec.Command("ls", "-a", "-l")
+    out, err := cmd.Output()
+    if err != nil {
+        panic(err)
+    }
+    fmt.Println("Files:")
+    fmt.Print(string(out))
 }
 
 // todo: full command lines with bash
diff --git a/063-execing-processes/execing-processes.go b/063-execing-processes/execing-processes.go
index dd6c9d8..1603b31 100644
--- a/063-execing-processes/execing-processes.go
+++ b/063-execing-processes/execing-processes.go
@@ -7,14 +7,14 @@ import "os"
 import "os/exec"
 
 func main() {
-	binary, lookErr := exec.LookPath("ls")
-	if lookErr != nil {
-		panic(lookErr)
-	}
-	execErr := syscall.Exec(binary, []string{"-a", "-l", "-h"}, os.Environ())
-	if execErr != nil {
-		panic(execErr)
-	}
+    binary, lookErr := exec.LookPath("ls")
+    if lookErr != nil {
+        panic(lookErr)
+    }
+    execErr := syscall.Exec(binary, []string{"-a", "-l", "-h"}, os.Environ())
+    if execErr != nil {
+        panic(execErr)
+    }
 }
 
 // todo: note lack of fork
diff --git a/064-signals/signals.go b/064-signals/signals.go
index 168d8b4..7dfa0ac 100644
--- a/064-signals/signals.go
+++ b/064-signals/signals.go
@@ -2,21 +2,26 @@
 
 package main
 
-import ("fmt"; "os"; "os/signal"; "syscall")
+import (
+    "fmt"
+    "os"
+    "os/signal"
+    "syscall"
+)
 
 func main() {
-	c := make(chan os.Signal, 1)
-	d := make(chan bool, 1)
+    c := make(chan os.Signal, 1)
+    d := make(chan bool, 1)
 
-	signal.Notify(c, syscall.SIGINT)
-	go func(){
-		sig := <- c
-		fmt.Println()
-		fmt.Println(sig)
-		d <- true
-	}()
-	fmt.Println("Awaiting signal")
-	<- d
+    signal.Notify(c, syscall.SIGINT)
+    go func() {
+        sig := <-c
+        fmt.Println()
+        fmt.Println(sig)
+        d <- true
+    }()
+    fmt.Println("Awaiting signal")
+    <-d
 }
 
 // todo: sending signals?
diff --git a/065-exit/exit.go b/065-exit/exit.go
index d8dec26..ad4c531 100644
--- a/065-exit/exit.go
+++ b/065-exit/exit.go
@@ -1,16 +1,16 @@
 // Exit
 
-package main            
+package main
 
 // Use `os.Exit` to immediatly exit with a given
 // status.
-import  "os"
+import "os"
 
 func main() {
     // This `println` will never be reached because the
     // exit is immediate.
-    defer println("!")  
-	os.Exit(3)  
+    defer println("!")
+    os.Exit(3)
 }
 
 // todo: discuss building before getting here
diff --git a/066-http-client/http-client.go b/066-http-client/http-client.go
index 79a043b..bca3223 100644
--- a/066-http-client/http-client.go
+++ b/066-http-client/http-client.go
@@ -7,11 +7,11 @@ import "io/ioutil"
 import "fmt"
 
 func main() {
-	resp, err := http.Get("http://127.0.0.1:5000/")
-	if err != nil {
-		panic(err)
-	}
-	defer resp.Body.Close()
-	body, err := ioutil.ReadAll(resp.Body)
-	fmt.Print(string(body))
+    resp, err := http.Get("http://127.0.0.1:5000/")
+    if err != nil {
+        panic(err)
+    }
+    defer resp.Body.Close()
+    body, err := ioutil.ReadAll(resp.Body)
+    fmt.Print(string(body))
 }
diff --git a/067-https-client/https-client.go b/067-https-client/https-client.go
index f5c8d08..7b58a24 100644
--- a/067-https-client/https-client.go
+++ b/067-https-client/https-client.go
@@ -8,13 +8,15 @@ import "io/ioutil"
 import "fmt"
 
 func main() {
-	tr := &http.Transport{
-		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
-	}
-	client := &http.Client{Transport: tr}
-	resp, err := client.Get("https://127.0.0.1:5000/")
-	if err != nil { panic(err) }
-	defer resp.Body.Close()
-	body, _ := ioutil.ReadAll(resp.Body)
-	fmt.Print(string(body))
+    tr := &http.Transport{
+        TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
+    }
+    client := &http.Client{Transport: tr}
+    resp, err := client.Get("https://127.0.0.1:5000/")
+    if err != nil {
+        panic(err)
+    }
+    defer resp.Body.Close()
+    body, _ := ioutil.ReadAll(resp.Body)
+    fmt.Print(string(body))
 }
diff --git a/068-redis/redis.go b/068-redis/redis.go
index b58c83f..da15664 100644
--- a/068-redis/redis.go
+++ b/068-redis/redis.go
@@ -7,60 +7,70 @@ import "time"
 import "fmt"
 
 func main() {
-	// initialize
-	conf := redis.DefaultConfig()
-	client := redis.NewClient(conf)
-	fmt.Println(conf)
-	fmt.Println(client)
+    // initialize
+    conf := redis.DefaultConfig()
+    client := redis.NewClient(conf)
+    fmt.Println(conf)
+    fmt.Println(client)
 
-	// set & get
-	setRep := client.Set("foo", "bar")
-	if setRep.Err != nil { panic(setRep.Err) }
-	fmt.Println(setRep)
-	getRep := client.Get("foo")
-	if getRep.Err != nil { panic(getRep.Err) }
-	getStr, _ := getRep.Str()
-	fmt.Println(getRep)	
-	fmt.Println(getStr)
+    // set & get
+    setRep := client.Set("foo", "bar")
+    if setRep.Err != nil {
+        panic(setRep.Err)
+    }
+    fmt.Println(setRep)
+    getRep := client.Get("foo")
+    if getRep.Err != nil {
+        panic(getRep.Err)
+    }
+    getStr, _ := getRep.Str()
+    fmt.Println(getRep)
+    fmt.Println(getStr)
 
-	// varadic calls
-	client.Set("foo1", "bar1")
-	client.Set("foo2", "bar2")
-	client.Set("foo3", "bar3")
-	mgetRep := client.Mget("foo1", "foo2", "foo3")
-	fmt.Println(mgetRep)
+    // varadic calls
+    client.Set("foo1", "bar1")
+    client.Set("foo2", "bar2")
+    client.Set("foo3", "bar3")
+    mgetRep := client.Mget("foo1", "foo2", "foo3")
+    fmt.Println(mgetRep)
 
     // multi calls
-	mcallRep := client.MultiCall(func(mc *redis.MultiCall) {
-		mc.Set("k1", "v1")
-		mc.Get("k1")
-	})
-	if mcallRep.Err != nil { panic(mcallRep.Err) }
-	mcallVal, _ := mcallRep.Elems[1].Str()
-	fmt.Println(mcallVal)
+    mcallRep := client.MultiCall(func(mc *redis.MultiCall) {
+        mc.Set("k1", "v1")
+        mc.Get("k1")
+    })
+    if mcallRep.Err != nil {
+        panic(mcallRep.Err)
+    }
+    mcallVal, _ := mcallRep.Elems[1].Str()
+    fmt.Println(mcallVal)
 
-	// transactional calls
-	tranRep := client.Transaction(func(mc *redis.MultiCall) {
-	  mc.Set("k2", "v2")
-	  mc.Get("k2")
-	})
-	if tranRep.Err != nil { panic(tranRep.Err) }
-	tranStr, _ := tranRep.Elems[1].Str()
-	fmt.Println(tranStr)
+    // transactional calls
+    tranRep := client.Transaction(func(mc *redis.MultiCall) {
+        mc.Set("k2", "v2")
+        mc.Get("k2")
+    })
+    if tranRep.Err != nil {
+        panic(tranRep.Err)
+    }
+    tranStr, _ := tranRep.Elems[1].Str()
+    fmt.Println(tranStr)
 
-	// pubsub
-	msgHdlr := func(msg *redis.Message) {
-		fmt.Println(msg)
-	}
-	sub, subErr := client.Subscription(msgHdlr)
-	if subErr != nil { panic(subErr) }
-	defer sub.Close()
-	sub.Subscribe("chan1", "chan2")
-	sub.Psubscribe("chan*")
-	client.Publish("chan1", "foo")
-	sub.Unsubscribe("chan1")
-	client.Publish("chan2", "bar")
-	time.Sleep(time.Second)
+    // pubsub
+    msgHdlr := func(msg *redis.Message) {
+        fmt.Println(msg)
+    }
+    sub, subErr := client.Subscription(msgHdlr)
+    if subErr != nil {
+        panic(subErr)
+    }
+    defer sub.Close()
+    sub.Subscribe("chan1", "chan2")
+    sub.Psubscribe("chan*")
+    client.Publish("chan1", "foo")
+    sub.Unsubscribe("chan1")
+    client.Publish("chan2", "bar")
+    time.Sleep(time.Second)
 }
 
 // todo: connection pooling & concurrency?
diff --git a/069-postgres/postgres.go b/069-postgres/postgres.go
index 62dbcb4..54a09f3 100644
--- a/069-postgres/postgres.go
+++ b/069-postgres/postgres.go
@@ -8,46 +8,60 @@ import "time"
 import "fmt"
 
 func main() {
-	db, openErr := sql.Open("postgres", "dbname=gobyexample sslmode=disable")
-	if openErr != nil { panic(openErr) }
-	defer db.Close()
-	fmt.Println(db)
-
-	createRep, createErr := db.Exec("CREATE TABLE items (a int, b float, c boolean, d text, e timestamp with time zone)")
-	if createErr != nil { panic(createErr) }
-	fmt.Println(createRep)
-
-	insertRep, insertErr := db.Exec("INSERT INTO items VALUES (1, 2.0, false, 'string', '2000-01-01T01:02:03Z')")
-	if insertErr != nil { panic(insertErr) }
-	fmt.Println(insertRep)
-
-	t1, _ := time.Parse(time.RFC3339, "2000-04-08T03:02:01Z")
-	t2, _ := time.Parse(time.RFC3339, "2007-03-02T10:15:45Z")
-	minsertRep, minsertErr := db.Exec("Insert INTO items VALUES ($1, $2, $3, $4, $5), ($6, $7, $8, $9, $10)",
-									  3, 7.0, true,  "more", t1,
-									  5, 1.0, false, "less", t2)
-	if minsertErr != nil { panic(minsertErr) }
-	num, _ := minsertRep.RowsAffected()
-	fmt.Println(num)
-
-	rows, selectErr := db.Query("SELECT * FROM items")
-	if selectErr != nil { panic(selectErr) }
-	defer rows.Close()
-	for rows.Next() {
-	  var r1 int
-	  var r2 float64
-	  var r3 bool
-	  var r4 string
-	  var r5 time.Time
-	  rows.Scan(&r1, &r2, &r3, &r4, &r5)
-	  fmt.Println(r1, r2, r3, r4, r5)
+    db, openErr := sql.Open("postgres", "dbname=gobyexample sslmode=disable")
+    if openErr != nil {
+        panic(openErr)
     }
-	rowsErr := rows.Err()
-	if rowsErr != nil { panic(rowsErr) }
-	
-	dropRep, dropErr := db.Exec("DROP TABLE items")
-	if dropErr != nil { panic(dropErr) }
-	fmt.Println(dropRep)
+    defer db.Close()
+    fmt.Println(db)
+
+    createRep, createErr := db.Exec("CREATE TABLE items (a int, b float, c boolean, d text, e timestamp with time zone)")
+    if createErr != nil {
+        panic(createErr)
+    }
+    fmt.Println(createRep)
+
+    insertRep, insertErr := db.Exec("INSERT INTO items VALUES (1, 2.0, false, 'string', '2000-01-01T01:02:03Z')")
+    if insertErr != nil {
+        panic(insertErr)
+    }
+    fmt.Println(insertRep)
+
+    t1, _ := time.Parse(time.RFC3339, "2000-04-08T03:02:01Z")
+    t2, _ := time.Parse(time.RFC3339, "2007-03-02T10:15:45Z")
+    minsertRep, minsertErr := db.Exec("Insert INTO items VALUES ($1, $2, $3, $4, $5), ($6, $7, $8, $9, $10)",
+        3, 7.0, true, "more", t1,
+        5, 1.0, false, "less", t2)
+    if minsertErr != nil {
+        panic(minsertErr)
+    }
+    num, _ := minsertRep.RowsAffected()
+    fmt.Println(num)
+
+    rows, selectErr := db.Query("SELECT * FROM items")
+    if selectErr != nil {
+        panic(selectErr)
+    }
+    defer rows.Close()
+    for rows.Next() {
+        var r1 int
+        var r2 float64
+        var r3 bool
+        var r4 string
+        var r5 time.Time
+        rows.Scan(&r1, &r2, &r3, &r4, &r5)
+        fmt.Println(r1, r2, r3, r4, r5)
+    }
+    rowsErr := rows.Err()
+    if rowsErr != nil {
+        panic(rowsErr)
+    }
+
+    dropRep, dropErr := db.Exec("DROP TABLE items")
+    if dropErr != nil {
+        panic(dropErr)
+    }
+    fmt.Println(dropRep)
 }
 
 // todo: connection pooling & concurrency
diff --git a/070-sending-email/sending-email.go b/070-sending-email/sending-email.go
index 94abd29..490a86a 100644
--- a/070-sending-email/sending-email.go
+++ b/070-sending-email/sending-email.go
@@ -5,21 +5,23 @@ package main
 import "net/smtp"
 
 func main() {
-	auth := smtp.PlainAuth(
-		"",
-		"mark@heroku.com",
-		"xxx",
-		"smtp.gmail.com",
-	)
+    auth := smtp.PlainAuth(
+        "",
+        "mark@heroku.com",
+        "xxx",
+        "smtp.gmail.com",
+    )
 
-	err := smtp.SendMail(
-		"smtp.gmail.com:25",
-		auth,
-		"mark+sent@heroku.com",
-		[]string{"mark@heroku.com"},
-		[]byte("nThe body."),
-	)
-	if err != nil { panic(err) }
+    err := smtp.SendMail(
+        "smtp.gmail.com:25",
+        auth,
+        "mark+sent@heroku.com",
+        []string{"mark@heroku.com"},
+        []byte("nThe body."),
+    )
+    if err != nil {
+        panic(err)
+    }
 }
 
 // todo: missing subject, cc, bcc
diff --git a/071-hello-web/hello-web.go b/071-hello-web/hello-web.go
index d5a65d7..a6b6819 100644
--- a/071-hello-web/hello-web.go
+++ b/071-hello-web/hello-web.go
@@ -6,7 +6,7 @@ import "net/http"
 
 func hello(res http.ResponseWriter, req *http.Request) {
     res.Header().Set("Content-Type", "text/plain")
-	res.Write([]byte("Hello web\n"))
+    res.Write([]byte("Hello web\n"))
 }
 
 func main() {
diff --git a/072-responses/responses.go b/072-responses/responses.go
index bb9671e..458aeb1 100644
--- a/072-responses/responses.go
+++ b/072-responses/responses.go
@@ -6,13 +6,13 @@ import "net/http"
 import "fmt"
 
 func hello(res http.ResponseWriter, req *http.Request) {
-	res.Header().Set("Content-Type", "text/plain")
-	if req.URL.Path == "/protected" {
-		res.WriteHeader(401)
-		fmt.Fprintln(res, "Not allowed")
-	} else {
-		fmt.Fprintln(res, "Hello")
-	}	
+    res.Header().Set("Content-Type", "text/plain")
+    if req.URL.Path == "/protected" {
+        res.WriteHeader(401)
+        fmt.Fprintln(res, "Not allowed")
+    } else {
+        fmt.Fprintln(res, "Hello")
+    }
 }
 
 func main() {
diff --git a/073-request-routing/request-routing.go b/073-request-routing/request-routing.go
index a1a585f..365bfe3 100644
--- a/073-request-routing/request-routing.go
+++ b/073-request-routing/request-routing.go
@@ -7,13 +7,13 @@ import "net/http"
 import "fmt"
 
 func hello(w http.ResponseWriter, req *http.Request) {
-	fmt.Fprintln(w, "hello " + req.URL.Query().Get(":name"))
+    fmt.Fprintln(w, "hello "+req.URL.Query().Get(":name"))
 }
 
 func main() {
-	p := pat.New()
-	p.Get("/hello/:name", http.HandlerFunc(hello))
-	http.ListenAndServe(":5000", p)
+    p := pat.New()
+    p.Get("/hello/:name", http.HandlerFunc(hello))
+    http.ListenAndServe(":5000", p)
 }
 
 // todo: consider gorilla-web
diff --git a/074-request-logging/request-logging.go b/074-request-logging/request-logging.go
index 7af01dc..eacb10e 100644
--- a/074-request-logging/request-logging.go
+++ b/074-request-logging/request-logging.go
@@ -7,32 +7,32 @@ import "time"
 import "fmt"
 
 func runLogging(logs chan string) {
-	for log := range logs {
-		fmt.Println(log)
-	}
+    for log := range logs {
+        fmt.Println(log)
+    }
 }
 
 func wrapLogging(f http.HandlerFunc) http.HandlerFunc {
-	logs := make(chan string, 10000)
-	go runLogging(logs)
-	return func(res http.ResponseWriter, req *http.Request) {
-		start := time.Now()
-		f(res, req)
-		method := req.Method
-		path := req.URL.Path
-		elapsed := float64(time.Since(start)) / 1000000.0
-		logs <- fmt.Sprintf("method=%s path=%s elapsed=%f", method, path, elapsed)
-	}
+    logs := make(chan string, 10000)
+    go runLogging(logs)
+    return func(res http.ResponseWriter, req *http.Request) {
+        start := time.Now()
+        f(res, req)
+        method := req.Method
+        path := req.URL.Path
+        elapsed := float64(time.Since(start)) / 1000000.0
+        logs <- fmt.Sprintf("method=%s path=%s elapsed=%f", method, path, elapsed)
+    }
 }
 
 func hello(res http.ResponseWriter, req *http.Request) {
     res.Header().Set("Content-Type", "text/plain")
-	time.Sleep(time.Millisecond * 50)
-	fmt.Fprintln(res, "Hello logged world")
+    time.Sleep(time.Millisecond * 50)
+    fmt.Fprintln(res, "Hello logged world")
 }
 
 func main() {
-	handler := wrapLogging(hello)
+    handler := wrapLogging(hello)
     http.HandleFunc("/", handler)
     http.ListenAndServe(":5000", nil)
 }
diff --git a/075-static-content/static-content.go b/075-static-content/static-content.go
index 52c3672..c15056e 100644
--- a/075-static-content/static-content.go
+++ b/075-static-content/static-content.go
@@ -5,8 +5,8 @@ package main
 import "net/http"
 
 func main() {
-	handler := http.FileServer(http.Dir("./"))
-	http.ListenAndServe(":5000", handler)
+    handler := http.FileServer(http.Dir("./"))
+    http.ListenAndServe(":5000", handler)
 }
 
 // todo: index pages
diff --git a/076-basic-authentication/basic-authentication.go b/076-basic-authentication/basic-authentication.go
index cecb132..fb31752 100644
--- a/076-basic-authentication/basic-authentication.go
+++ b/076-basic-authentication/basic-authentication.go
@@ -3,44 +3,44 @@
 package main
 
 import (
-	"net/http"
-	"encoding/base64"
-	"strings"
-	"fmt"
+    "encoding/base64"
+    "fmt"
+    "net/http"
+    "strings"
 )
 
 type Authenticator func(string, string) bool
 
 func testAuth(r *http.Request, auth Authenticator) bool {
-	s := strings.SplitN(r.Header.Get("Authorization"), " ", 2)
-	if len(s) != 2 || s[0] != "Basic" {
-		return false
-	}
-	b, err := base64.StdEncoding.DecodeString(s[1])
-	if err != nil {
-		return false
-	}
-	pair := strings.SplitN(string(b), ":", 2)
-	if len(pair) != 2 {
-		return false
-	}
-	return auth(pair[0], pair[1])
+    s := strings.SplitN(r.Header.Get("Authorization"), " ", 2)
+    if len(s) != 2 || s[0] != "Basic" {
+        return false
+    }
+    b, err := base64.StdEncoding.DecodeString(s[1])
+    if err != nil {
+        return false
+    }
+    pair := strings.SplitN(string(b), ":", 2)
+    if len(pair) != 2 {
+        return false
+    }
+    return auth(pair[0], pair[1])
 }
 
 func requireAuth(w http.ResponseWriter, r *http.Request) {
-	w.Header().Set("WWW-Authenticate", `Basic realm="private"`)
-	w.WriteHeader(401)
-	w.Write([]byte("401 Unauthorized\n"))
+    w.Header().Set("WWW-Authenticate", `Basic realm="private"`)
+    w.WriteHeader(401)
+    w.Write([]byte("401 Unauthorized\n"))
 }
 
 func wrapAuth(h http.HandlerFunc, a Authenticator) http.HandlerFunc {
     return func(w http.ResponseWriter, r *http.Request) {
-    	if testAuth(r, a) {
-		  h(w, r)
-		} else {
-		  requireAuth(w, r)
-		}
-	}
+        if testAuth(r, a) {
+            h(w, r)
+        } else {
+            requireAuth(w, r)
+        }
+    }
 }
 
 func hello(w http.ResponseWriter, r *http.Request) {
@@ -48,10 +48,10 @@ func hello(w http.ResponseWriter, r *http.Request) {
 }
 
 func main() {
-	checkPassword := func(_, password string) bool {
-		return password == "supersecret"
-	}
-	handler1 := http.HanderFunc(hello)
-	handler2 := wrapAuth(handler1, checkPassword)
+    checkPassword := func(_, password string) bool {
+        return password == "supersecret"
+    }
+    handler1 := http.HanderFunc(hello)
+    handler2 := wrapAuth(handler1, checkPassword)
     http.ListenAndServe(":5000", handler2)
 }
diff --git a/077-canonical-hosts/canonical-hosts.go b/077-canonical-hosts/canonical-hosts.go
index b53ab01..56e7897 100644
--- a/077-canonical-hosts/canonical-hosts.go
+++ b/077-canonical-hosts/canonical-hosts.go
@@ -8,26 +8,26 @@ import "fmt"
 
 func hello(res http.ResponseWriter, req *http.Request) {
     res.Header().Set("Content-Type", "text/plain")
-	fmt.Fprintln(res, "Hello canonical world")
+    fmt.Fprintln(res, "Hello canonical world")
 }
 
 func wrapCanonicalHost(f http.HandlerFunc, canonicalHost string) http.HandlerFunc {
-	return func(res http.ResponseWriter, req *http.Request) {
-		hostPort := strings.Split(req.Host, ":")
-		host := hostPort[0]
-		if host != canonicalHost {
-			fmt.Println("redirecting from", host, "to", canonicalHost)
-			hostPort[0] = canonicalHost
-			url := "http://" + strings.Join(hostPort, ":") + req.URL.String()
-			http.Redirect(res, req, url, 301)
-			return
-		}
-		f(res, req)
-	}
+    return func(res http.ResponseWriter, req *http.Request) {
+        hostPort := strings.Split(req.Host, ":")
+        host := hostPort[0]
+        if host != canonicalHost {
+            fmt.Println("redirecting from", host, "to", canonicalHost)
+            hostPort[0] = canonicalHost
+            url := "http://" + strings.Join(hostPort, ":") + req.URL.String()
+            http.Redirect(res, req, url, 301)
+            return
+        }
+        f(res, req)
+    }
 }
 
 func main() {
-	handler := wrapCanonicalHost(hello, "localhost")
+    handler := wrapCanonicalHost(hello, "localhost")
     http.HandleFunc("/", handler)
     http.ListenAndServe(":5000", nil)
 }
diff --git a/078-middleware/middleware.go b/078-middleware/middleware.go
index 6f85166..d7486f0 100644
--- a/078-middleware/middleware.go
+++ b/078-middleware/middleware.go
@@ -7,19 +7,19 @@ import "fmt"
 
 func hello(res http.ResponseWriter, req *http.Request) {
     res.Header().Set("Content-Type", "text/plain")
-	fmt.Fprintln(res, "Hello wrapped world")
+    fmt.Fprintln(res, "Hello wrapped world")
 }
 
 func wrapMiddleware(f http.HandlerFunc) http.HandlerFunc {
-	return func(res http.ResponseWriter, req *http.Request) {
-		fmt.Println("before")
-		f(res, req)
-		fmt.Println("after")		
-	}
+    return func(res http.ResponseWriter, req *http.Request) {
+        fmt.Println("before")
+        f(res, req)
+        fmt.Println("after")
+    }
 }
 
 func main() {
-	handler := wrapMiddleware(hello)
+    handler := wrapMiddleware(hello)
     http.HandleFunc("/", handler)
     http.ListenAndServe(":5000", nil)
 }
diff --git a/079-graceful-shutdown/graceful-shutdown.go b/079-graceful-shutdown/graceful-shutdown.go
index 27ec0e5..5f45849 100644
--- a/079-graceful-shutdown/graceful-shutdown.go
+++ b/079-graceful-shutdown/graceful-shutdown.go
@@ -3,88 +3,92 @@
 package main
 
 import (
+    "fmt"
     "net"
     "net/http"
-    "time"
     "os"
     "os/signal"
-    "syscall"
-    "fmt"
     "sync/atomic"
+    "syscall"
+    "time"
 )
 
 func slow(res http.ResponseWriter, req *http.Request) {
-	fmt.Println("respond at=start")
-	time.Sleep(time.Second * 5)
-	res.Header().Set("Content-Type", "text/plain")
-	fmt.Fprintln(res, "Finally.")
-	fmt.Println("respond at=finish")
+    fmt.Println("respond at=start")
+    time.Sleep(time.Second * 5)
+    res.Header().Set("Content-Type", "text/plain")
+    fmt.Fprintln(res, "Finally.")
+    fmt.Println("respond at=finish")
 }
 
 var connCount int64 = 0
 
 type watchedConn struct {
-	net.Conn
+    net.Conn
 }
 
 func (w *watchedConn) Close() error {
-	atomic.AddInt64(&connCount, -1)
- 	return w.Conn.Close()
+    atomic.AddInt64(&connCount, -1)
+    return w.Conn.Close()
 }
 
 type watchedListener struct {
-	net.Listener
+    net.Listener
 }
 
 func (l *watchedListener) Accept() (net.Conn, error) {
-	conn, err := l.Listener.Accept()
-	if err != nil {
-		return nil, err
-	}
-	atomic.AddInt64(&connCount, 1)
-	return &watchedConn{Conn: conn}, nil
+    conn, err := l.Listener.Accept()
+    if err != nil {
+        return nil, err
+    }
+    atomic.AddInt64(&connCount, 1)
+    return &watchedConn{Conn: conn}, nil
 }
 
 func main() {
-	stop := make(chan bool, 1)
-	sig := make(chan os.Signal, 1)
-	
-	server := &http.Server{Handler: http.HandlerFunc(slow)}
-	fmt.Println("listen at=start")
-	listener, listenErr := net.Listen("tcp", ":5000")
-	if listenErr != nil { panic(listenErr) }
-	wListener := &watchedListener{Listener: listener}
-	fmt.Println("listen at=finish")
+    stop := make(chan bool, 1)
+    sig := make(chan os.Signal, 1)
 
-	go func() {
-		<- stop
-		fmt.Println("close at=start")
-		closeErr := wListener.Close()
-		if closeErr != nil { panic(closeErr) }
-		fmt.Println("close at=finish")
-	}()
+    server := &http.Server{Handler: http.HandlerFunc(slow)}
+    fmt.Println("listen at=start")
+    listener, listenErr := net.Listen("tcp", ":5000")
+    if listenErr != nil {
+        panic(listenErr)
+    }
+    wListener := &watchedListener{Listener: listener}
+    fmt.Println("listen at=finish")
 
-	go func() {
-		signal.Notify(sig, syscall.SIGINT, syscall.SIGTERM)
-		fmt.Println("trap at=start")
-		<- sig
-		stop <- true
-		fmt.Println("trap at=finish")
-	}()
+    go func() {
+        <-stop
+        fmt.Println("close at=start")
+        closeErr := wListener.Close()
+        if closeErr != nil {
+            panic(closeErr)
+        }
+        fmt.Println("close at=finish")
+    }()
 
-	fmt.Println("serve at=start")
-	server.Serve(wListener)	
-	fmt.Println("serve at=finish")
-	for {
-		connCountCurrent := atomic.LoadInt64(&connCount)
-		if connCountCurrent > 0 {
-			fmt.Println("wait at=pending remaining=", connCountCurrent)
-			time.Sleep(time.Second)
-		} else {
-			fmt.Println("wait at=finish remaining=", connCountCurrent)
-			return
-		}
-	}
+    go func() {
+        signal.Notify(sig, syscall.SIGINT, syscall.SIGTERM)
+        fmt.Println("trap at=start")
+        <-sig
+        stop <- true
+        fmt.Println("trap at=finish")
+    }()
+
+    fmt.Println("serve at=start")
+    server.Serve(wListener)
+    fmt.Println("serve at=finish")
+    for {
+        connCountCurrent := atomic.LoadInt64(&connCount)
+        if connCountCurrent > 0 {
+            fmt.Println("wait at=pending remaining=", connCountCurrent)
+            time.Sleep(time.Second)
+        } else {
+            fmt.Println("wait at=finish remaining=", connCountCurrent)
+            return
+        }
+    }
 }
 
 // todo: clean up logging
diff --git a/082-sha1-hashes/sha1-hashes.go b/082-sha1-hashes/sha1-hashes.go
index f637bd9..d451c41 100644
--- a/082-sha1-hashes/sha1-hashes.go
+++ b/082-sha1-hashes/sha1-hashes.go
@@ -1,29 +1,29 @@
 // ## SHA1 Hashes                                    
-                                         
-package main                             
-                    
+
+package main
+
 // Package `crypto/sha1` computes SHA1 hashes.                       
-import "crypto/sha1"                              
-import "encoding/hex"                       
+import "crypto/sha1"
+import "encoding/hex"
 import "fmt"
-                                         
-func main() {             
+
+func main() {
     // The pattern is `sha1.New()`, `sha1.Write(bytes)`,               
     // then `sha1.Sum([]byte{})
-    h := sha1.New()                      
-                                         
+    h := sha1.New()
+
     // `Write` expects bytes. If you have a string `s`     
     // use `[]byte(s)` to coerce it.                                
-    h.Write([]byte("sha1 this string")) 
-                                         
+    h.Write([]byte("sha1 this string"))
+
     // Get the result. The argument to `Sum` can be used
     // to append to an existing buffer: usually uneeded.                                     
-    bs := h.Sum(nil)                     
-                                         
+    bs := h.Sum(nil)
+
     // SHA1 values are often printed in hex, for example   
     // with git.                                  
-    fmt.Println(hex.EncodeToString(bs))                                           
-}                                        
+    fmt.Println(hex.EncodeToString(bs))
+}
 
 // You can compute other hashes using a similar
 // pattern. For exmpale, to compute MD5 hashes
diff --git a/084-https-server/https-servers.go b/084-https-server/https-servers.go
index 11a69e3..4bd253b 100644
--- a/084-https-server/https-servers.go
+++ b/084-https-server/https-servers.go
@@ -5,12 +5,14 @@ package main
 import "net/http"
 
 func handler(res http.ResponseWriter, req *http.Request) {
-	res.Header().Set("Content-Type", "text/plain")
-	res.Write([]byte("Hello from HTTPS\n"))
+    res.Header().Set("Content-Type", "text/plain")
+    res.Write([]byte("Hello from HTTPS\n"))
 }
 
 func main() {
-	http.HandleFunc("/", handler)
-	err := http.ListenAndServeTLS(":5000", "/tmp/server.crt", "/tmp/server.key", nil)
-	if err != nil { panic(err) }
+    http.HandleFunc("/", handler)
+    err := http.ListenAndServeTLS(":5000", "/tmp/server.crt", "/tmp/server.key", nil)
+    if err != nil {
+        panic(err)
+    }
 }
diff --git a/tool/number.go b/tool/number.go
index e6c66a4..08f2a6a 100644
--- a/tool/number.go
+++ b/tool/number.go
@@ -6,14 +6,14 @@ package main
 import (
     "fmt"
     "io/ioutil"
-    "strings"
-    "regexp"
     "os"
+    "regexp"
     "sort"
+    "strings"
 )
 
 func minInt(a, b int) int {
-    if (a < b) {
+    if a < b {
         return a
     }
     return b
@@ -24,7 +24,9 @@ func main() {
     sourceNames := make([]string, 0)
     sourceMap := make(map[string]string)
     fileInfos, dirErr := ioutil.ReadDir("./")
-    if dirErr != nil { panic(dirErr) }
+    if dirErr != nil {
+        panic(dirErr)
+    }
     baseTrimmer, _ := regexp.Compile("[0-9x]+-")
     for _, fi := range fileInfos {
         baseName := baseTrimmer.ReplaceAllString(fi.Name(), "")
@@ -36,15 +38,17 @@ func main() {
 
     // read names from index
     indexBytes, idxErr := ioutil.ReadFile("tool/index.txt")
-    if idxErr != nil { panic (idxErr) }
+    if idxErr != nil {
+        panic(idxErr)
+    }
     indexNamesAll := strings.Split(string(indexBytes), "\n")
     indexNames := make([]string, 0)
     for _, indexName := range indexNamesAll {
-        if indexName != "" && !strings.Contains(indexName, "#") && !strings.Contains(indexName, "~")  {
+        if indexName != "" && !strings.Contains(indexName, "#") && !strings.Contains(indexName, "~") {
             indexNames = append(indexNames, indexName)
         }
     }
-    
+
     // sanity check two lists
     if len(sourceNames) != len(indexNames) {
         sort.Strings(sourceNames)
@@ -54,7 +58,7 @@ func main() {
         }
         os.Exit(1)
     }
-    
+
     // rename some stuff
     for index, indexName := range indexNames {
         oldName := sourceMap[indexName]