如何從失敗的命令返回退出代碼 0

Question

我想從失敗的命令中返回退出代碼“0”。 有沒有更簡單的方法可以做到這一點，而不是：

function a() {
  ls aaaaa 2>&1;
}

if ! $(a); then
  return 0
else
  return 5
fi

Answer 1

只需將return 0附加到函數即可強制函數始終成功退出。

function a() {
  ls aaaaa 2>&1
  return 0
}

a
echo $? # prints 0

如果您出於任何原因希望內聯，您可以附加|| true || true命令：

ls aaaaa 2>&1 || true
echo $? # prints 0

如果您想反轉退出狀態，只需在命令前加上!

! ls aaaaa 2>&1
echo $? # prints 0

! ls /etc/resolv.conf 2>&1
echo $? # prints 1

此外，如果您說明您想要實現的總體目標，我們可能會指導您獲得更好的答案。

Answer 2

對於希望輸入（如 SIGINT = 鍵盤中斷）停止的命令，嘗試timeout命令可能會有所幫助，例如：

timeout 10 kubectl proxy &

這將執行 kubectl 代理 10 秒（因此您可以使用代理執行所需的操作），然后將正常終止kubectl proxy

例子：

timeout 3 kubectl proxy &
[1] 759
Starting to serve on 127.0.0.1:8001

echo $?
0

超時的幫助也將有助於特定情況

timeout --help
Usage: timeout [OPTION] DURATION COMMAND [ARG]...
  or:  timeout [OPTION]
Start COMMAND, and kill it if still running after DURATION.

Mandatory arguments to long options are mandatory for short options too.
      --preserve-status
                 exit with the same status as COMMAND, even when the
                   command times out
      --foreground
                 when not running timeout directly from a shell prompt,
                   allow COMMAND to read from the TTY and get TTY signals;
                   in this mode, children of COMMAND will not be timed out
  -k, --kill-after=DURATION
                 also send a KILL signal if COMMAND is still running
                   this long after the initial signal was sent
  -s, --signal=SIGNAL
                 specify the signal to be sent on timeout;
                   SIGNAL may be a name like 'HUP' or a number;
                   see 'kill -l' for a list of signals
      --help     display this help and exit
      --version  output version information and exit