如何检查Perl的system()中管道中第一个程序的状态? [英] How can I check the status of the first program in pipeline in Perl's system()?

问题描述

perl -e 'system ("crontab1 -l");print $?'

按预期返回-1(程序crontab1不存在)

returns -1 as expected (program crontab1 doesn't exist)

perl -e 'system ("crontab1 -l|grep blah");print $?'

返回256.

如何检查第一个(或两个)程序的状态?

What is the way to check the status of the first (or both) programs?

推荐答案

您将以应有的方式获取整个命令的退出状态.如果要分别退出状态，则必须分别运行命令.

You are getting the exit status of the entire command, just as you should. If you want the exit status separately, you're going to have to run the commands separately.

#!/usr/bin/perl -e
system("crontab1 -l > /tmp/junk.txt"); print $?;
system("grep blah /tmp/junk.txt"); print $?;

作为示例.

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