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|
#!/bin/sh
set -eu
usage() {
cat <<-'EOF'
Usage:
free-port
free-port -h
EOF
}
help() {
cat <<-'EOF'
Options:
-h, --help show this message
Returns a free TCP port.
Examples:
Get a port for a command:
$ cmd -p `free-port`
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 $((OPTIND - 1))
PORT=1024
while true; do
if ! lsof -s TCP:LISTEN -i ":$PORT" >/dev/null; then
break
fi
PORT=$((PORT + 1))
done
echo "$PORT"
|
