Set-e and Set-o in Linux Pipefail

1, SET-E

"Exit immediately if a simple command exits with a Non-zero status."

In the code that appears after "Set-e", once the return value is nonzero, the entire script exits immediately.

2, Set-o Pipefail

"If set, the return value of a pipeline is the value of the last (rightmost) command to exit with a Non-zero status,or Z  Ero if all commands in the pipeline exit successfully. This option was disabled by default. "

After this setting is executed, its subsequent code, including the return value of the pipe command, returns a value for the last nonzero command, or returns zero when all the commands inside the pipeline are executed successfully.

As shown in the following example:

When the Set-o Pipifail is not set

#!/bin.bash# There is no a.test,but has b.testcat a.testecho $?cat b.testecho $?cat b.test | echo "HI" echo $?

Cat A.test | echo "HI"
echo $?

The results of the implementation are as follows:

Linux-umlhem:/home/test/shell # sh-x tst.sh+ cat a.testcat:a.test:no such file or directory+ echo 11+ cat b.test----thi S is a test-----+ echo 00+ cat b.test+ echo hihi+ echo 00+ cat a.test+ echo hihicat:a.test:no such file or directory+ EC Ho 00

You can see the cat a.test in execution | echo "HI" returns the result of the rightmost command execution.

Here's an example of setting up Set-o pipeline, as follows:

Set-o Pipefailcat B.test | echo "HI" Echo $?cat a.test | echo "HI" echo $?

The output results are as follows:

+ Set-o pipefail+ cat b.test+ echo hihi+ echo 141141+ cat a.test+ echo hihicat:a.test:no such file or directory+ Echo 1 1

　　

Set-e and Set-o in Linux Pipefail