使用bash的子命令

Question

是否可以为bash脚本实现子命令.我有这样的想法:

http://docs.python.org/dev/library/argparse.html#sub-commands

Answer 1

这是一个简单的不安全技术:

#!/bin/bash

clean() {
  echo rm -fR .
  echo Thanks to koola, I let you off this time,
  echo but you really shouldn\'t run random code you download from the net.
}

help() {
  echo Whatever you do, don\'t use clean
}

args() {
  printf "%s" options:
  while getopts a:b:c:d:e:f:g:h:i:j:k:l:m:n:o:p:q:r:s:t:u:v:w:x:y:z: OPTION "$@"; do
    printf " -%s '%s'" $OPTION $OPTARG
  done
  shift $((OPTIND - 1))
  printf "arg: '%s'" "$@"
  echo
}

"$@"

这一切都很酷,但并不限制子命令的含义.所以你可能想用以下代码替换最后一行:

if [[ $1 =~ ^(clean|help|args)$ ]]; then
  "$@"
else
  echo "Invalid subcommand $1" >&2
  exit 1
fi

有些系统允许您在子命令之前放置"全局"选项.如果需要,可以getopts在子命令执行之前放置一个循环.记住shift在你进入子命令执行之前; 此外,重置OPTIND为1,以便子命令getopts不会混淆.