someCommand 2>&1 | grep pattern &
如何获取someCommand
的退出状态?
PIPESTATUS
不起作用,因为它是后台进程。
我发现了这个link,它似乎有效但只有当我使用它时才这样。简单echo
屏幕似乎不起作用。我想知道是否可以在不创建临时文件的情况下获取退出代码。
答案 0 :(得分:3)
在bash中你可以做到:
echo "${PIPESTATUS[0]} ${PIPESTATUS[1]}"
示例:
$ ls -l | grep somefile
-rw-rw-r-- 1 me me 32 May 4 15:47 somefile
$ echo "${PIPESTATUS[0]} ${PIPESTATUS[1]}"
0 0
$ ls -l 1>/dev/null | grep while
$ echo "${PIPESTATUS[0]} ${PIPESTATUS[1]}"
0 1
对于管道前景进程
如果脚本说的testscript.sh包含:
#!/bin/bash
echo "Some Stuff"
exit 29 # Some random exit code for testing
DO
$./testscript.sh | grep somestuff
$ echo "${PIPESTATUS[0]} ${PIPESTATUS[1]}"
29 1
对于管道后台进程
方法1:使用pipefail
对于包含以下内容的testscript.sh:
#!/bin/bash
set -eo pipefail
#set -o pipefail causes a pipeline to produce a failure return code
#If a command fails, set -e will make the whole script exit,
cat nonexistingfile # this command fails
echo "Some Stuff"
exit 29
做
$ ./testscript.sh 2>/dev/null | grep Some &
[2] 7684
$ fg 2
bash: fg: job has terminated
[2]- Exit 1 ./testscript.sh 2> /dev/null | grep --color=auto Some
您将获得退出状态1,从中您可以得出脚本失败的结论。
如果cat nonexistingfile
已删除,您将获得:
[2]- Done ./37257668.sh 2> /dev/null | grep --color=auto Some
Disdvantage :pipefail将为所有退出代码返回一个不是特定于失败命令的退出代码
方法2:来源shell脚本
$ . ./testscript.sh 2>/dev/null | grep Some & #mind the dot in the beginning
$ echo "${PIPESTATUS[0]} ${PIPESTATUS[1]}"
29 0
最后触摸
如果您怀疑shell脚本中的单个命令失败,那么测试脚本可以在下面执行:
#no shebang
echo "Some Stuff"
ls non_existent 2>/dev/null || ls__return_value=50
做
$. ./testscript | grep "Some"
$if [ $ls__return_value -eq 50 ]; then echo "Error in ls"; fi
答案 1 :(得分:1)
您可以将保存PIPESTATUS内容的代码放在{ ... }
内的临时文件中,然后在后台运行。如果我们对管道中多个命令的退出代码感兴趣,则需要这种方法:
{
someCommand 2>&1 | grep -- pattern
printf "0=%s\n1=%s\n" "${PIPESTATUS[0]}" "${PIPESTATUS[1]}" > status.out
} &
wait "$!"
# grab the exit code from status.out file
{
someCommand 2>&1 | grep -- pattern
exit ${PIPESTATUS[0]}
} &
wait "$!"
echo $? # this is the exit code of someCommand
等待:等待[n]
Wait for the specified process and report its termination status. If N is not given, all currently active child processes are waited for, and the return code is zero. N may be a process ID or a job specification; if a job spec is given, all processes in the job's pipeline are waited for.