The role of "SET-E" in the "Go" unix/linux script

Original link: http://blog.csdn.net/todd911/article/details/9954961

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#!/bin/bash

Set-e

Command 1
Command 2
...

Exit 0
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Every script you write should include Set-e at the top. This tells bash, it should exit the script if any statement returns a non-true return value. The benefit of USING-E is that it prevents errors snowballing to serious issues when they could has been caught Earlie R. Again, for readability-want to use Set-o errexit.

Each script you write should be prefixed with SET-E at the beginning of the file, which tells Bash to exit if the execution of any statement is not true. The upside is to prevent mistakes from snowball-like to cause a fatal error that should have been dealt with before. If you want to increase readability, you can use Set-o Errexit, which works the same as SET-E.

USING-E gives you error checking for free. If you forget to check something, bash would do it for you. Unfortunately it means you can ' t check $? As bash would never get to the checking code if it isn ' t zero. There is other constructs your could use:

Use-e to help you check for errors. If you forget to check (execute the result of the statement), Bash will do it for you. Unfortunately, you will not be able to check $? Because if the executed statement is not returned 0,bash will not be able to execute into the checked code. You can use other structures:

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1. Command
2. If ["$?" -ne 0]; Then
3. echo "Command failed";
4. Exit 1;
5. Fi

Could is replaced with

can be substituted for

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1. Command | | {echo "command failed"; exit 1;}

Or

Or

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1. if! Command Then
2. echo "Command failed";
3. Exit 1;
4. Fi

What if you had a command that returns Non-zero or is not the interested in its return value? can use command | | True, or if you had a longer section of code that you can turn off the error checking, but I recommend you use this sparingly .

If you have a command that returns non-0 or you don't care about the result of the statement execution, you can use command | | True, or you have a very long code, you can turn off error checking (do not use set-e), but I suggest you use this statement conservatively.

The role of "SET-E" in the "Go" unix/linux script