shell,python,perl（面向过程） 面向对象：shell，
$mkdirusers2>errors.txt $caterrors.txt mkdir: cannot create directory ‘users’: File exists Most of the time, it is difficult to find the exact line number in scripts. To print the line number with the error, use thePS4option (supported with Bash 4.1 or later). Example below: ...
echo 'Must supply a parameter, exiting.' >&2 exit 1 ;; *) echo 'Unknown error, exiting.' >&2 exit $status esac
and should therefore be avoided for user-specified exit parameters. Ending a script withexit 127would certainly cause confusion when troubleshooting (is the error code a"command not found" or a user-defined one?). However, many scripts use anexit 1as a general bailout-upon-error....
The if in a Bash script is a shell keyword that is used to test conditions based on the exit status of a test command. An exit status of zero, and only zero, is a success, i.e. a condition that is true. Any other exit status is a failure, i.e. a condition that is false. ...
cd/foo ||exit1 bar baz bat ...# Lots of commands. 出错时,cd 命令会报告无法改变当前目录,同时将错误消息输出到标准错误,例如 "bash: cd: /foo: No such file or directory"。如果你想要在标准输出同时输出自定义的错误提示,可以使用复合命令(command grouping[17]): ...
soyuka commented on Feb 14, 2017 soyuka on Feb 14, 2017 Collaborator IMO it's just because you've a spawn and that pm2 also spawns: -- pm2 --- node index.js (process container) --- bash test.sh Perhaps the bash script is trying to exit (on error maybe), and isn't being ...
echo "$instances instance(s) of this script running." echo "[Hit Ctl-C to exit.]"; echo sleep 1 # 等一下. bash $0 # 再来一次, Sam. exit 0 # 没必要; 脚本永远不会运行到这里. # 为什么运行不到这里? # 在使用Ctl-C退出之后, ...
If the error is unrecoverable and you want to exit the script, choose this. This will give you the same effect as set -e, exiting at the error.echo Many long and complex actions false echo Many more long and complex actionsNote it exited after false, and the final echo statement never...
Bash Pitfalls[1]文章介绍了 40 多条日常 Bash 编程中,老手和新手都容易忽略的错误编程习惯。每条作者在给出错误的范例上,详细分析与解释错误的原因,同时给出正确的改写建议。文中有不少引用的文章,也值得大家仔细阅读。仔细阅读了这篇文章后,收获很多,不感独享,把这篇文章以半翻译半笔记的形式分享给大家。