Bash
trim() in Bash: Strip Leading and Trailing Whitespace
PHP-style trim(), ltrim() and rtrim() in pure Bash with parameter expansion, plus why the popular read trick quietly removes your backslashes.
Category
Bash
The pure Bash function library (PHP-style helpers written in Bash) and practical shell scripting techniques.
Bash
__pgrepf() in Bash: pgrep -f Using Only /proc
Find processes by their full command line in pure Bash by reading /proc/PID/cmdline, with the NUL bytes handled properly and the 2009 bugs fixed.
Bash
emptydir() in Bash: Check Whether a Directory Is Empty
Test whether a directory is empty in pure Bash with nullglob and dotglob, handle hidden and unreadable directories, and know when find -quit is faster.
Bash
strlen() in Bash: Get the Length of a String
Bash's ${#var} counts characters, PHP's strlen() counts bytes. A clean strlen() function, a strbytes() companion, and the locale traps in between.
Bash
strtolower() in Bash: Convert a String to Lowercase
A strtolower() for Bash 4 and the stock macOS Bash 3.2, why ${var,,} depends on your locale, and when declare -l, tr, awk or nocasematch fit better.
Bash
strtoupper() in Bash: Convert a String to Uppercase
A strtoupper() that works on Bash 4+ and macOS's Bash 3.2, plus ${var^^pattern} for uppercasing only some characters and declare -u for variables.
Bash
stristr() in Bash: Case-Insensitive Substring Search
Check whether a string contains a substring regardless of case, with a Bash 4 version, a Bash 3.2 fallback using nocasematch, and a PHP-style stristr().
Bash
strstr() in Bash: Check if a String Contains a Substring
Test whether a string contains a substring in pure Bash, or get the rest of the string from the first match the way PHP's strstr() does.
Bash
dirname() in Bash: Get the Directory Part of a Path
Get the directory part of a path in pure Bash, matching coreutils dirname on trailing slashes, bare names and the root, without starting a process.
Bash
yesno() in Bash: Ask a Yes/No Question Safely
A yes/no confirmation prompt for Bash scripts that accepts any case, has an optional default and handles cron, pipes and EOF without looping forever.