ltrim.bash

#!/usr/bin/env bash
#@ Function : trim ltrim rtrim trimv trimall
#@ Desc     : Delete leading/trailing blank characters from a string or
#@          : stream.
#@          :
#@          : Blank charaters are space, tab, and new-line.
#@          :
#@          :   trim    strip string/file of leading+trailing blank chars.
#@          :   ltrim   strip string/file of leading blank chars.
#@          :   rtrim   strip string/file of trailing blank chars.
#@          :   trimv   assign stripped string to variable.
#@          :   trimall strip string/file of trailing blank chars and double spaces within string.
#@          :
#@ Synopsis : trim [-e] string|-
#@          : ltrim string|-
#@          : rtrim string|-
#@          : trimv -n varname string|-
#@          : trimall string|-
#@          :
#@ Examples : #0) strip spaces from around 'str'
#@          : str=" 123 "; str=$(trim "$str")
#@          :
#@          : #1) remove all leading+trailing blanks.
#@          : trim <fat.file >thin.file
#@          :
#@          : #2) remove trailing blanks from file.
#@          : rtrim <fat.file >lean.file
#@          :
#@          : #3) remove all leading+trailing blanks from file, scenic route.
#@          : rtrim <fat.file | ltrim >thin.file
#@          :
#@          : #4) Assign stripped string to varname.
#@          : trimv -n myvar "  This   is  a messy string.  "
#@          : echo "$myvar"
#@          :
ltrim() {
	if(($#)); then
		local v="$*"
		echo "${v#"${v%%[![:blank:]]*}"}"
	else
		local REPLY
		while IFS= read -r; do
			echo "${REPLY#"${REPLY%%[![:blank:]]*}"}"
		done
	fi
}
declare -fx ltrim