update manuscript

manuscript/chapter0.txt

@@ -1,10 +1,10 @@
-# Introduction
+# FOREWORD
 
-A collection of pure `bash` alternatives to external processes and programs. The `bash` scripting language is more powerful than people realise and you can accomplish most tasks without the need or dependency of external programs.
+A collection of pure `bash` alternatives to external processes and programs. The `bash` scripting language is more powerful than people realise and most tasks can be accomplished without the need for or dependence on external programs.
 
-Calling an external process in `bash` is expensive and excessive use will cause a noticeable slowdown. By sticking to built-in methods (*where possible*) your scripts and programs will be faster, require less dependencies and you'll gain a better understanding of the language itself.
+Calling an external process in `bash` is expensive and excessive use will cause a noticeable slowdown. Scripts and programs written using built-in methods (*where applicable*) will be faster, require less dependencies and afford a better understanding of the language itself.
 
-The contents of this book provide a reference for solving the problems encountered when writing programs and scripts in `bash`. The examples are in function format showcasing how to incorporate these solutions into your code.
+The content of this book provides a reference for solving problems encountered when writing programs and scripts in `bash`. Examples are in function format showcasing how to incorporate these solutions into code.
 
 <!-- CHAPTER END -->
 

manuscript/chapter1.txt

@@ -1,4 +1,4 @@
-# Strings
+# STRINGS
 
 ## Trim leading and trailing white-space from string
 
@@ -353,7 +353,7 @@ if [[ "$var" == sub_string* ]]; then
     printf '%s\n' "var starts with sub_string."
 fi
 
-# Inverse (var doesn't start with sub_string).
+# Inverse (var does not start with sub_string).
 if [[ "$var" != sub_string* ]]; then
     printf '%s\n' "var does not start with sub_string."
 fi
@@ -366,7 +366,7 @@ if [[ "$var" == *sub_string ]]; then
     printf '%s\n' "var ends with sub_string."
 fi
 
-# Inverse (var doesn't start with sub_string).
+# Inverse (var does not start with sub_string).
 if [[ "$var" != *sub_string ]]; then
     printf '%s\n' "var does not end with sub_string."
 fi

manuscript/chapter10.txt

@@ -1,4 +1,4 @@
-# Arithmetic
+# ARITHMETIC
 
 ## Simpler syntax to set variables
 
@@ -16,7 +16,7 @@
 ((var=var2*arr[2]))
 ```
 
-## Ternary tests
+## Ternary Tests
 
 ```shell
 # Set the value of var to var2 if var2 is greater than var.

manuscript/chapter11.txt

@@ -1,8 +1,8 @@
-# Traps
+# TRAPS
 
-Traps allow you to execute code on various signals. In `pxltrm` I'm using traps to redraw the user interface on window resize. Another use case is cleaning up temporary files on script exit.
+Traps allow a script to execute code on various signals. In [pxltrm](https://github.com/dylanaraps/pxltrm) (*a pixel art editor written in bash*)  traps are used to redraw the user interface on window resize. Another use case is cleaning up temporary files on script exit.
 
-These `trap` lines should be added near the start of your script so any early errors are also caught.
+Traps should be added near the start of scripts so any early errors are also caught.
 
 **NOTE:** For a full list of signals, see `trap -l`.
 

manuscript/chapter12.txt

@@ -1,8 +1,8 @@
-# Performance
+# PERFORMANCE
 
 ## Disable Unicode
 
-If your script doesn't require unicode, you can disable it for a speed boost. Results may vary but I've seen an improvement in Neofetch and some other smaller programs.
+If unicode is not required, it can be disabled for a performance increase. Results may vary however there have been noticeable improvements in [neofetch](https://github.com/dylanaraps/neofetch) and other programs.
 
 ```shell
 # Disable unicode.

manuscript/chapter13.txt

@@ -1,4 +1,4 @@
-# Obsolete Syntax
+# OBSOLETE SYNTAX
 
 ## Shebang
 
@@ -34,7 +34,7 @@ var="$(command "$(command)")"
 
 ## Function Declaration
 
-Don't use the `function` keyword, it reduces compatibility with older versions of `bash`.
+Do not use the `function` keyword, it reduces compatibility with older versions of `bash`.
 
 ```shell
 # Right.

manuscript/chapter14.txt

@@ -1,10 +1,4 @@
-# Internal Variables
-
-**NOTE**: This list does not include every internal variable (*You can
-help by adding a missing entry!*).
-
-For a complete list, see:
-http://tldp.org/LDP/abs/html/internalvariables.html
+# INTERNAL VARIABLES
 
 ## Get the location to the `bash` binary
 

manuscript/chapter15.txt

@@ -1,4 +1,4 @@
-# Information about the terminal
+# INFORMATION ABOUT THE TERMINAL
 
 ## Get the terminal size in lines and columns (*from a script*)
 

manuscript/chapter16.txt

@@ -1,4 +1,4 @@
-# Conversion
+# CONVERSION
 
 ## Convert a hex color to RGB
 
@@ -42,7 +42,7 @@ $ rgb_to_hex "255" "255" "255"
 ```
 
 
-# Code Golf
+# CODE GOLF
 
 ## Shorter `for` loop syntax
 
@@ -80,13 +80,13 @@ f(){ echo hi;}
 f()(echo hi)
 
 # Using arithmetic
-# You can use this to assign integer values.
+# This can be used to assign integer values.
 # Example: f a=1
 #          f a++
 f()(($1))
 
 # Using tests, loops etc.
-# NOTE: You can also use ‘while’, ‘until’, ‘case’, ‘(())’, ‘[[]]’.
+# NOTE: ‘while’, ‘until’, ‘case’, ‘(())’, ‘[[]]’ can also be used.
 f()if true; then echo "$1"; fi
 f()for i in "$@"; do echo "$i"; done
 ```

manuscript/chapter17.txt

@@ -1,9 +1,8 @@
-# Other
+# OTHER
 
 ## Use `read` as an alternative to the `sleep` command
 
-I was surprised to find out `sleep` is an external command and isn't a
-built-in.
+Surprisingly, `sleep` is an external command and not a `bash` built-in.
 
 **CAVEAT:** Requires `bash` 4+
 
@@ -28,8 +27,7 @@ read_sleep 30
 ## Check if a program is in the user's PATH
 
 ```shell
-# There are 3 ways to do this and you can use either of
-# these in the same way.
+# There are 3 ways to do this and either one can be used.
 type -p executable_name &>/dev/null
 hash executable_name &>/dev/null
 command -v executable_name &>/dev/null
@@ -44,9 +42,9 @@ if ! type -p executable_name &>/dev/null; then
     # Program is not in PATH.
 fi
 
-# Example (Exit early if program isn't installed).
+# Example (Exit early if program is not installed).
 if ! type -p convert &>/dev/null; then
-    printf '%s\n' "error: convert isn't installed, exiting..."
+    printf '%s\n' "error: convert is not installed, exiting..."
     exit 1
 fi
 ```
@@ -158,7 +156,7 @@ done
 printf '\n'
 ```
 
-## Get the list of functions from your script
+## Get the list of functions in a script
 
 ```sh
 get_functions() {

manuscript/chapter2.txt

@@ -1,4 +1,4 @@
-# Arrays
+# ARRAYS
 
 ## Reverse an array
 
@@ -92,7 +92,7 @@ $ array=(red green blue yellow brown)
 $ random_array_element "${array[@]}"
 yellow
 
-# You can also just pass multiple arguments.
+# Multiple arguments can also be passed.
 $ random_array_element 1 2 3 4 5 6 7
 3
 ```

manuscript/chapter3.txt

@@ -1,8 +1,8 @@
-# Loops
+# LOOPS
 
 ## Loop over a range of numbers
 
-Don't use `seq`.
+Alternative to `seq`.
 
 ```shell
 # Loop from 0-100 (no variable support).
@@ -13,7 +13,7 @@ done
 
 ## Loop over a variable range of numbers
 
-Don't use `seq`.
+Alternative to `seq`.
 
 ```shell
 # Loop from 0-VAR.

manuscript/chapter4.txt

@@ -1,6 +1,6 @@
-# File handling
+# FILE HANDLING
 
-**CAVEAT:** `bash` doesn't handle binary data properly in versions `< 4.4`.
+**CAVEAT:** `bash` does not handle binary data properly in versions `< 4.4`.
 
 ## Read a file to a string
 
@@ -92,8 +92,7 @@ lines() {
 
 **Example Function (bash 3):**
 
-This method uses less memory than the `mapfile` method and it's more
-compatible but it's slower for bigger files.
+This method uses less memory than the `mapfile` method and works in `bash` 3 but it is slower for bigger files.
 
 ```sh
 lines_loop() {

manuscript/chapter5.txt

@@ -1,4 +1,4 @@
-# File Paths
+# FILE PATHS
 
 ## Get the directory name of a file path
 

manuscript/chapter6.txt

@@ -1,4 +1,4 @@
-# Variables
+# VARIABLES
 
 ## Assign and access a variable using a variable
 

manuscript/chapter7.txt

@@ -1,6 +1,6 @@
-# Escape Sequences
+# ESCAPE SEQUENCES
 
-Contrary to popular belief, there's no issue in using raw escape sequences. Using `tput` just abstracts the same ANSI escape sequences. What's worse is that `tput` isn't actually portable, there are a number of different `tput` variants on different Operating Systems each with different commands (*try and run `tput setaf 3` on a FreeBSD system*). The easiest solution ends up being raw ANSI sequences.
+Contrary to popular belief, there is no issue in utilizing raw escape sequences. Using `tput` abstracts the same ANSI sequences as if printed manually. Worse still, `tput` is not actually portable. There are a number of `tput` variants each with different commands and syntaxes (*try `tput setaf 3` on a FreeBSD system*). Raw sequences are fine.
 
 ## Text Colors
 

manuscript/chapter8.txt

@@ -1,4 +1,4 @@
-# Parameter Expansion
+# PARAMETER EXPANSION
 
 ## Indirection
 
@@ -58,7 +58,7 @@
 | `${VAR-STRING}` | If `VAR` is unset, use `STRING` as it's value.
 | `${VAR:=STRING}` | If `VAR` is empty or unset, set the value of `VAR` to `STRING`.
 | `${VAR=STRING}` | If `VAR` is unset, set the value of `VAR` to `STRING`.
-| `${VAR:+STRING}` | If `VAR` isn't empty, use `STRING` as it's value.
+| `${VAR:+STRING}` | If `VAR` is not empty, use `STRING` as it's value.
 | `${VAR+STRING}` | If `VAR` is set, use `STRING` as it's value.
 | `${VAR:?STRING}` | Display an error if empty or unset.
 | `${VAR?STRING}` | Display an error if unset.

manuscript/chapter9.txt

@@ -1,4 +1,4 @@
-# Brace Expansion
+# BRACE EXPANSION
 
 ## Ranges