忽略Shell脚本中的特定错误 [英] Ignoring specific errors in a shell script

问题描述

我有一小段shell脚本，有可能引发许多错误.我目前已将该脚本设置为全局停止所有错误.但是，我希望此小节有所不同.

I have a small snippet of a shell script which has the potential to throw many errors. I have the script currently set to globally stop on all errors. However i would like for this small sub-section is slightly different.

以下是代码段:

recover database using backup controlfile until cancel || true; 
auto

我期望这最终会引发找不到文件"错误.但是，我想继续执行此错误.对于其他任何错误，我希望脚本停止.

I'm expecting this to eventually throw a "file not found" error. However i would like to continue executing on this error. For any other error i would like the script to stop.

实现此目标的最佳方法是什么?

What would be the best method of achieving this?

Bash版本3.00.16

Bash Version 3.00.16

推荐答案

为了防止bash忽略特定命令的错误，您可以说:

In order to prevent bash to ignore error for specific commands you can say:

some-arbitrary-command || true

这将使脚本继续.例如，如果您具有以下脚本:

This would make the script continue. For example, if you have the following script:

$ cat foo
set -e
echo 1
some-arbitrary-command || true
echo 2

执行它会返回:

$ bash foo
1
z: line 3: some-arbitrary-command: command not found
2

在命令行中没有|| true的情况下，它会产生:

In the absence of || true in the command line, it'd have produced:

$ bash foo
1
z: line 3: some-arbitrary-command: command not found

手册中的报价:

如果失败的命令是其中的一部分，则外壳不会退出 紧随while或until关键字之后的命令列表，属于 if语句中的测试，该测试是在&&中执行的任何命令的一部分，或者 ||列表，但最后一个&&或||之后的命令除外 在管道中但最后一个管道中，或者命令的返回状态为 用!反转. ERR上的陷阱(如果已设置)在外壳程序之前执行 退出.

The shell does not exit if the command that fails is part of the command list immediately following a while or until keyword, part of the test in an if statement, part of any command executed in a && or || list except the command following the final && or ||, any command in a pipeline but the last, or if the command’s return status is being inverted with !. A trap on ERR, if set, is executed before the shell exits.

为了更改行为，以便仅在执行some-arbitrary-command作为错误一部分返回file not found的情况下，继续执行 ，您可以说:

In order to change the behaviour such that in the execution should continue only if executing some-arbitrary-command returned file not found as part of the error, you can say:

[[ $(some-arbitrary-command 2>&1) =~ "file not found" ]]

作为示例，执行以下操作(不存在名为MissingFile.txt的文件):

As an example, execute the following (no file named MissingFile.txt exists):

$ cat foo 
#!/bin/bash
set -u
set -e
foo() {
  rm MissingFile.txt
}
echo 1
[[ $(foo 2>&1) =~ "No such file" ]]
echo 2
$(foo)
echo 3

这将产生以下输出:

$ bash foo 
1
2
rm: cannot remove `MissingFile.txt': No such file or directory

请注意，已执行echo 2，但未执行.

Note that echo 2 was executed but echo 3 wasn't.

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