Unix/Linux 脚本中 “set -e” 的作用

转载自：http://www.linuxidc.com/Linux/2009-07/21072.htm

Unix/Linux 脚本中 "set -e" 的作用

example:

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#!/bin/bash

set -e

command 1

command 2

...

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Use set -e 

Every script you write should include set -e at the top. This tells bash that 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 into serious issues when they could have
been caught earlier. Again, for readability you may want to use set -o errexit.

Using -e gives you error checking for free. If you forget to check something, bash will do it or you. Unfortunately it means you can't check $? as bash will never get to the checking code if it isn't zero. There are other constructs you could use:

commandif [ "$?"-ne 0]; then echo "command failed"; exit 1; fi

could be replaced with

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

or

if ! command; then echo "command failed"; exit 1; fi

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