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|
#!/bin/sh
set -eu
usage() {
cat <<-'EOF'
Usage:
assert-arg -- STRING MESSAGE
assert-arg -h
EOF
}
help() {
cat <<-'EOF'
Options:
-h, --help show this message
STRING the string to check if is empty
MESSAGE the message to print when STRING is empty
Examples:
Assert that $1 contains an argument, named FILENAME:
$ eval "$(assert-arg -- "${1:-}" 'FILENAME')"
EOF
}
for flag in "$@"; do
case "$flag" in
--)
break
;;
--help)
usage
help
exit
;;
*)
;;
esac
done
while getopts 'h' flag; do
case "$flag" in
h)
usage
help
exit
;;
*)
usage >&2
exit 2
;;
esac
done
shift $((OPTIND - 1))
STRING="${1:-}"
MESSAGE="${2:-}"
if [ -z "$MESSAGE" ]; then
printf 'Missing MESSAGE, an argument to assert-arg.\n\n' >&2
usage >&2
exit 2
fi
if [ -z "$STRING" ]; then
printf 'Missing %s.\n\n' "$MESSAGE" >&2
cat <<-'EOF'
usage >&2
exit 2
EOF
fi
|
