Shell Scripting Learning Summary 11--script debugging

Parameters:

-N does not execute script, only checks syntax for errors

-V Output the script contents to the screen and execute the script

-X executes the script and outputs the content to the screen

-N

-V

Ten module () {  eval '/usr/bin/modulecmd bash $*'}#/bin/bashif [$15  ];then   "Yes"or "else"     No " Fiyes

-X

[[Email protected] sbin]# SH-'['5']'   2operator  expected+ echo Nono

Expand:

Use PS4 to make debugging output line numbers

[[email protected] sbin]# echo $PS 4+[[email protected] sbin]# export PS4='+{$LINENO}  '[[email protected] sbin]# Sh-x debug.sh 4
+{2} ' [' 4-gt 5 '] '
+{5}echo No
No

Use set to narrow the scope of debugging

Set-x Turn on debug function

Set +x turn off the debug function

[email protected] sbin]# Cat demo.sh #/bin/bash./etc/init.d/functionsSet-Xread-P"pleas input your anwser[yes/no]:" anSet+xif[[$an =Yes]] Then action"The answer is true"/bin/trueElseAction"Then answer is False"/bin/falsefi[[email protected] sbin]# sh demo.sh+{4}read-p'pleas input your anwser[yes/no]:'Anpleas Input your anwser[yes/No]: Yes+{5}Set+XThe Answer is true[OK]

Shell Scripting Learning Summary 11--script debugging