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Print argument list for testing

snipplet:
debug, arguments
LastUpdate:
2013-03-23
Contributor:
Snappy (IRC), Dan Douglas
type:
snipplet

Sometimes you might find it useful to see how arguments passed to a program arrive there.

Check this script (save it as script file or make a function):

printf '"%b"\n' "$0" "$@" | nl -v0 -s": "

It uses the printf command to generate a list of arguments, even with escape sequences interpreted. This list is shown formatted by the nl(1) utility.

Another alternative with colorized output. If run in Bash, it temporarily disables all debug output for itself, including the test that determines whether to hide debug output. In ksh, tracing would have to be enabled on the function to show debug output, so it works out to being equivalent.

# Bash or ksh93 debugging function for colored display of argv.
# Optionally set OFD to the desired output file descriptor.
function args {
	{ BASH_XTRACEFD=3 command eval ${BASH_VERSION+"$(</dev/fd/0)"}; } <<-'EOF' 3>/dev/null
		case $- in *x*)
			set +x
			trap 'trap RETURN; set -x' RETURN
		esac
EOF
 
	[[ ${OFD-1} == +([0-9]) ]] || return
 
	if [[ -t ${OFD:-2} ]]; then
		typeset -A clr=([green]=$(tput setaf 2) [sgr0]=$(tput sgr0))
	else
		typeset clr
	fi
 
	if ! ${1+false}; then
		printf -- "${clr[green]}<${clr[sgr0]}%s${clr[green]}>${clr[sgr0]} " "$@"
		echo
	else
		echo 'no args.'
	fi >&"${OFD:-2}"
}

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snipplets/prargs.txt · Last modified: 2013/03/23 17:25 by ormaaj
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