我对打印父进程的变体:

ps -p $$ | awk '$1 == PP {print $4}' PP=$$

当AWK可以为您运行不必要的应用程序时，不要运行它。

There are three approaches to finding the name of the current shell's executable: Please note that all three approaches can be fooled if the executable of the shell is /bin/sh, but it's really a renamed bash, for example (which frequently happens). Thus your second question of whether ps output will do is answered with "not always". echo $0 - will print the program name... which in the case of the shell is the actual shell. ps -ef | grep $$ | grep -v grep - this will look for the current process ID in the list of running processes. Since the current process is the shell, it will be included. This is not 100% reliable, as you might have other processes whose ps listing includes the same number as shell's process ID, especially if that ID is a small number (for example, if the shell's PID is "5", you may find processes called "java5" or "perl5" in the same grep output!). This is the second problem with the "ps" approach, on top of not being able to rely on the shell name. echo $SHELL - The path to the current shell is stored as the SHELL variable for any shell. The caveat for this one is that if you launch a shell explicitly as a subprocess (for example, it's not your login shell), you will get your login shell's value instead. If that's a possibility, use the ps or $0 approach. If, however, the executable doesn't match your actual shell (e.g. /bin/sh is actually bash or ksh), you need heuristics. Here are some environmental variables specific to various shells: $version is set on tcsh $BASH is set on bash $shell (lowercase) is set to actual shell name in csh or tcsh $ZSH_NAME is set on zsh ksh has $PS3 and $PS4 set, whereas the normal Bourne shell (sh) only has $PS1 and $PS2 set. This generally seems like the hardest to distinguish - the only difference in the entire set of environment variables between sh and ksh we have installed on Solaris boxen is $ERRNO, $FCEDIT, $LINENO, $PPID, $PS3, $PS4, $RANDOM, $SECONDS, and $TMOUT.

没有一个答案适用于fish shell(它没有变量$$或$0)。

这适用于我(测试在sh, bash, fish, ksh, csh, true, tcsh，和zsh;openSUSE 13.2):

ps | tail -n 4 | sed -E '2,$d;s/.* (.*)/\1/'

该命令输出类似bash的字符串。这里我只使用ps、tail和sed(没有GNU扩展;尝试添加——posix来检查它)。它们都是标准的POSIX命令。我相信尾巴是可以去掉的，但是我的sed fu还不够强。

在我看来，这个解决方案不是很可移植，因为它不能在OS x上工作:(

我尝试过许多不同的方法，对我来说最好的方法是:

ps -p $$

它也可以在Cygwin下工作，并且不能像PID grepping那样产生假阳性。经过一些清理，它只输出一个可执行名称(在Cygwin With path下):

ps -p $$ | tail -1 | awk '{print $NF}'

你可以创建一个函数，这样你就不必记住它:

# Print currently active shell
shell () {
  ps -p $$ | tail -1 | awk '{print $NF}'
}

…然后执行shell。

它在Debian和Cygwin下进行了测试。

不需要从"ps"的输出中Grepping PID，因为你可以从/proc目录结构中读取任何PID的相应命令行:

echo $(cat /proc/$$/cmdline)

然而，这可能并不比简单地:

echo $0

关于运行一个与名称不同的shell，一个想法是使用之前获得的名称从shell请求版本:

<some_shell> --version

sh似乎失败的退出码2，而其他人给出一些有用的(但我无法验证所有，因为我没有他们):

$ sh --version
sh: 0: Illegal option --
echo $?
2

如果您只是想检查您正在运行(特定版本的)Bash，最好的方法是使用$BASH_VERSINFO数组变量。作为一个(只读)数组变量，它不能在环境中设置， 因此，您可以确定它来自当前shell(如果有的话)。

但是，由于Bash在作为sh调用时具有不同的行为，因此还需要检查以/ Bash结尾的$ Bash环境变量。

在我写的一个脚本中，使用了带-(不是下划线)的函数名，并依赖于关联数组(在Bash 4中添加)，我有以下完整性检查(有有用的用户错误消息):

case `eval 'echo $BASH@${BASH_VERSINFO[0]}' 2>/dev/null` in
    */bash@[456789])
        # Claims bash version 4+, check for func-names and associative arrays
        if ! eval "declare -A _ARRAY && func-name() { :; }" 2>/dev/null; then
            echo >&2 "bash $BASH_VERSION is not supported (not really bash?)"
            exit 1
        fi
        ;;
    */bash@[123])
        echo >&2 "bash $BASH_VERSION is not supported (version 4+ required)"
        exit 1
        ;;
    *)
        echo >&2 "This script requires BASH (version 4+) - not regular sh"
        echo >&2 "Re-run as \"bash $CMD\" for proper operation"
        exit 1
        ;;
esac

在第一种情况下，您可以忽略对特性的功能检查，只假设将来的Bash版本是兼容的。