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In this article, the editor introduces in detail "what is the meaning of #! / usr/bin/perl in perl". The content is detailed, the steps are clear, and the details are handled properly. I hope this article "what is the meaning of #! / usr/bin/perl in perl" can help you solve your doubts.

The meaning of #! / usr/bin/perl in perl:

'#!' This symbol comes from unix.' #! / usr/bin/perl'- is actually a special comment that tells the operating system that the contents of this file should be executed by the perl program stored under / usr/bin/. Under Windows, this is not needed, and people are used to writing #! perl, just to show that this is a perl program.

The perl interpreter is usually placed in / usr/bin/perl or / usr/local/bin/perl.

If not, you need to find the location of the perl on your machine and use that path. On a Unix system, it is possible to find perl _ usr/bin/env perl by using the following line.

Purpose:

This symbol,! #, is usually written at the beginning of the first line of a script in a Unix system, and indicates the interpreter that executes the script file.

1. If there is no # in the script file! On this line, it defaults to interpreting the script with the current Shell (that is, the $SHELL environment variable) when it executes.

two。 If #! The later interpreter is an executable file, so when the script is executed, it passes the file name and its parameters as parameters to the interpreter for execution.

3. If #! If the specified interpreter does not have executable permission, an error "bad interpreter: Permission denied" will be reported. If #! If the specified interpreter is not an executable file, the specified interpreter is ignored and handed over to the current SHELL to execute the script.

4. If #! If the specified interpreter does not exist, an error "bad interpreter: No such file or directory" will be reported. Note: #! The later interpreter, which needs to write its absolute path (e.g. #! / bin/bash), will not automatically look for the interpreter in $PATH.

5. Of course, if you use commands like "bash test.sh" to execute the script, then #! This line will be ignored, and the interpreter will of course use the bash explicitly specified on the command line.

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