How can I call a shell command in my Perl script

Question

What would be an example of how I can call a shell command  say  ls -a  in a Perl script and the way to retrieve the output of the command as well

User · Answer

There are a lot of ways you can call a shell command from a Perl script, such as:

back tick ls which captures the output and gives back to you.
system system('ls');
open

Refer #17 here: Perl programming tips

User · Answer

Examples   ls -l   system  quot ls -l quot    exec  quot ls -l quot

User · Answer

You might want to look into open2 and open3 in case you need bidirectional communication

User · Answer

As you become more experienced with using Perl  you ll find that there are fewer and fewer occasions when you need to run shell commands   For example  one way to get a list of files is to use Perl s built-in glob function   If you want the list in sorted order you could combine it with the built-in sort function   If you want details about each file  you can use the stat function   Here s an example      usr bin perl  use strict  use warnings   foreach my  file   sort glob   home grant             my  dev  ino  mode  nlink  uid  gid  rdev  size  atime  mtime  ctime  blksize  blocks            stat  file       printf   -40s  8u bytes n    file   size

User · Answer

From Perl HowTo  the most common ways to execute external commands from Perl are    my  files    ls -la      captures the output of the command in  files system  touch   foo      if you don t want to capture the command s output exec  vim   foo      if you don t want to return to the script after executing the command open my  file    -    grep foo    print  file  foo nbar      if you want to pipe input into the command

User · Answer

Look at the open function in Perl - especially the variants using a      pipe  in the arguments   Done correctly  you ll get a file handle that you can use to read the output of the command   The back tick operators also do this   You might also want to review whether Perl has access to the C functions that the command itself uses   For example  for ls -a  you could use the opendir function  and then read the file names with the readdir function  and finally close the directory with  surprise  the closedir function   This has a number of benefits - precision probably being more important than speed   Using these functions  you can get the correct data even if the file names contain odd characters like newline

User · Answer

How to run a shell script from a Perl program     1  Using system system  command   arguments        For example    system  sh    script sh    --help      system  sh script sh --help          System will execute the  command with    arguments and return to your script when finished  You may check      for certain errors passed to the OS by the external application  Read   the documentation for system for the nuances of how various   invocations are slightly different       2  Using exec       This is very similar to the use of system  but it will   terminate your script upon execution  Again  read the documentation   for exec for more       3  Using backticks or qx     my  output    script sh --option    my  output   qx script sh --option         The backtick operator and it s equivalent qx    excute the command and options inside the operator and return that commands output to STDOUT when it finishes        There are also ways to run external applications through creative use of open  but this is advanced use  read the documentation for more

[perl] How can I call a shell command in my Perl script?

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