Create a functions file

functions.sh

@@ -0,0 +1,214 @@
+#!/usr/bin/env bash
+
+# Functions from:
+# https://github.com/dylanaraps/pure-bash-bible
+
+## Trim leading and trailing white-space from string
+trim_string() {
+ # Usage: trim_string " example string "
+ : "${1#"${1%%[![:space:]]*}"}"
+ : "${_%"${_##*[![:space:]]}"}"
+ printf '%s\n' "$_"
+}
+
+## Trim all white-space from string and truncate spaces
+
+# This is an alternative to `sed`, `awk`, `perl` and other tools. The
+# function below works by abusing word splitting to create a new string
+# without leading/trailing white-space and with truncated spaces.
+
+# shellcheck disable=SC2086,SC2048
+trim_all() {
+ # Usage: trim_all " example string "
+ set -f
+ set -- $*
+ printf '%s\n' "$*"
+ set +f
+}
+
+## Use regex on a string
+
+# The result of `bash`'s regex matching can be used to replace `sed` for a
+# large number of use-cases.
+
+# **CAVEAT**: This is one of the few platform dependant `bash` features.
+# `bash` will use whatever regex engine is installed on the user's system.
+# Stick to POSIX regex features if aiming for compatibility.
+
+# **CAVEAT**: This example only prints the first matching group. When using
+# multiple capture groups some modification is needed.
+regex() {
+ # Usage: regex "string" "regex"
+ [[ $1 =~ $2 ]] && printf '%s\n' "${BASH_REMATCH[1]}"
+}
+
+is_hex_color() {
+ # Usage:
+ # read -r color
+ # is_hex_color "$color" || color="#FFFFFF"
+ if [[ "$1" =~ ^(#?([a-fA-F0-9]{6}|[a-fA-F0-9]{3}))$ ]]; then
+ printf '%s\n' "${BASH_REMATCH[1]}"
+ else
+ printf '%s\n' "error: $1 is an invalid color."
+ return 1
+ fi
+}
+
+
+## Split a string on a delimiter
+# This is an alternative to `cut`, `awk` and other tools.
+split() {
+ # Usage: split "string" "delimiter"
+ # Multi char delimiters work too!
+ IFS=$'\n' read -d "" -ra arr <<< "${1//$2/$'\n'}"
+ printf '%s\n' "${arr[@]}"
+}
+
+
+## Change a string to lowercase
+# **CAVEAT:** Requires `bash` 4+
+lower() {
+ # Usage: lower "string"
+ printf '%s\n' "${1,,}"
+}
+
+## Change a string to uppercase
+# **CAVEAT:** Requires `bash` 4+
+upper() {
+ # Usage: upper "string"
+ printf '%s\n' "${1^^}"
+}
+
+## Trim quotes from a string
+trim_quotes() {
+ # Usage: trim_quotes "string"
+ : "${1//\'}"
+ printf '%s\n' "${_//\"}"
+}
+
+## Strip all instances of pattern from string
+```sh
+strip_all() {
+ # Usage: strip_all "string" "pattern"
+ printf '%s\n' "${1//$2}"
+}
+```
+
+# **Example Usage:**
+
+# ```shell
+# $ strip_all "The Quick Brown Fox" "[aeiou]"
+# Th Qck Brwn Fx
+
+# $ strip_all "The Quick Brown Fox" "[[:space:]]"
+# TheQuickBrownFox
+
+# $ strip_all "The Quick Brown Fox" "Quick "
+# The Brown Fox
+# ```
+
+## Strip first occurrence of pattern from string
+strip() {
+ # Usage: strip "string" "pattern"
+ printf '%s\n' "${1/$2}"
+}
+
+## Strip pattern from start of string
+lstrip() {
+ # Usage: lstrip "string" "pattern"
+ printf '%s\n' "${1##$2}"
+}
+
+## Strip pattern from end of string
+rstrip() {
+ # Usage: rstrip "string" "pattern"
+ printf '%s\n' "${1%%$2}"
+}
+
+reverse_array() {
+ # Usage: reverse_array "array"
+ shopt -s extdebug
+ f()(printf '%s\n' "${BASH_ARGV[@]}"); f "$@"
+ shopt -u extdebug
+}
+
+remove_array_dups() {
+ # Usage: remove_array_dups "array"
+ declare -A tmp_array
+
+ for i in "$@"; do
+ [[ "$i" ]] && IFS=" " tmp_array["${i:- }"]=1
+ done
+
+ printf '%s\n' "${!tmp_array[@]}"
+}
+
+random_array_element() {
+ # Usage: random_array_element "array or multiple arguments"
+ local arr=("$@")
+ printf '%s\n' "${arr[RANDOM % $#]}"
+}
+
+cycle() {
+ # Usage: cycle "array"
+ local arr=("$@")
+ printf '%s ' "${arr[${i:=0}]}"
+ ((i=i>=${#arr[@]}-1?0:++i))
+}
+
+head() {
+ # Usage: head "n" "file"
+ mapfile -tn "$1" line < "$2"
+ printf '%s\n' "${line[@]}"
+}
+
+tail() {
+ # Usage: tail "n" "file"
+ mapfile -tn 0 line < "$2"
+ printf '%s\n' "${line[@]: -$1}"
+}
+
+lines() {
+ # Usage: lines "file"
+ # Alternative to `wc -l`
+ mapfile -tn 0 lines < "$1"
+ printf '%s\n' "${#lines[@]}"
+}
+
+lines_loop() {
+ # Usage: lines_loop "file"
+ count=0
+ while IFS= read -r _; do
+ ((count++))
+ done < "$1"
+ printf '%s\n' "$count"
+}
+
+# Extract code blocks from MarkDown file.
+### $ extract ~/projects/pure-bash/README.md '```sh' '```'
+extract() {
+ # Usage: extract file "opening marker" "closing marker"
+ ## Extract lines between two markers
+ while IFS=$'\n' read -r line; do
+ [[ "$extract" && "$line" != "$3" ]] && \
+ printf '%s\n' "$line"
+
+ [[ "$line" == "$2" ]] && extract=1
+ [[ "$line" == "$3" ]] && extract=
+ done < "$1"
+}
+
+## Get the directory name of a file path
+### Alternative to the `dirname` command.
+dirname() {
+ # Usage: dirname "path"
+ printf '%s\n' "${1%/*}/"
+}
+
+## Get the base-name of a file path
+### Alternative to the `basename` command.
+basename() {
+ # Usage: basename "path"
+ : "${1%/}"
+ printf '%s\n' "${_##*/}"
+}