Unlock Powerful Bash Scripting with the Pure Bash Bible – Key Snippets & Tricks

Pure Bash Bible Overview

The open‑source "Pure Bash Bible" gathers a comprehensive set of Bash code snippets that let you perform common tasks without external dependencies, making scripts faster and more portable.

Key Functions

Trim whitespace

trim_string() {
    # Usage: trim_string "   example   string    "
    : "${1#"${1%%[![:space:]]*}"}"
    : "${_%"${_##*[![:space:]]}"}"
    printf %s "$_"
}

Example usage:

$ trim_string "    Hello,  World    "
Hello,  World
$ name="   John Black  "
$ trim_string "$name"
John Black

Regex matching

regex() {
    # Usage: regex "string" "regex"
    [[ $1 =~ $2 ]] && printf %s "${BASH_REMATCH[1]}"
}

Example usage:

$ regex    hello  ^s*(.*)
hello
$ regex "#FFFFFF" ^(#?([a-fA-F0-9]{6}|[a-fA-F0-9]{3}))$
#FFFFFF
$ regex "red" ^(#?([a-fA-F0-9]{6}|[a-fA-F0-9]{3}))$
# no output

Array deduplication

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 "${!tmp_array[@]}"
}

Example usage:

$ remove_array_dups 1 1 2 2 3 3 3 3 3 4 4 4 4 4 5 5 5 5 5 5
1
2
3
4
5
$ arr=(red red green blue blue)
$ remove_array_dups "${arr[@]}"
red
green
blue

The full collection of snippets is hosted on GitHub at https://github.com/dylanaraps/pure-bash-bible, where the project has gathered over 24 000 stars and 2 000 forks.