Create a functions file

Wanted to source this from my .bash_profile
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Trey Brister 2018-10-16 02:58:34 -05:00 committed by GitHub
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#!/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"
: "${1%/}"
printf '%s\n' "${_##*/}"
}