Perl is excellent "glueware" - a language which can be well used to connect together a whole lot of elements. And one of those elements may be operating system commands run from within the Perl program.

Here are (three!) ways that you can do it - in each case leaving the result of running the commands in a scalar variable.

# CAUTION - OS Dependent!
 
$imc = `uname -m`;
 
$imd = qx!uname -r!;
 
$imcalled = <<`DONE`
uname -s
date
uptime
DONE
;
 
# CAUTION - OS Dependent!
 
print ("***** Here document:\n$imcalled\n");
print ("***** Backquote:\n$imc\n");
print ("***** qx:\n$imd");

So that's
* A text string of commands in backquotes
* A text string of commands in a 'qx' string
* A text block (here document)

And here's how it runs:

BirthdayBoy:csr1 grahamellis$ perl bq
***** Here document:
Darwin
Tue 8 Jul 2008 18:41:38 BST
18:41 up 31 mins, 2 users, load averages: 0.01 0.05 0.06
 
***** Backquote:
Power Macintosh
 
***** qx:
9.0.0
BirthdayBoy:csr1 grahamellis$

You can also run operating system commands via a piped file handle, where you'll read back the response line by line:

open (FH,"ls -l *.*|");
while ($line = <FH>) {
  print ++$n," ",$line;
  }

Which gives us ...

BirthdayBoy:csr1 grahamellis$ perl lbl
1 -rw-r--r-- 1 grahamellis grahamellis 2856 7 Jul 16:35 dis.txt
2 -rw-r--r-- 1 grahamellis grahamellis 825 8 Jul 09:24 fred.txt
3 -rw-r--r-- 1 grahamellis grahamellis 3 7 Jul 10:04 pod2htmd.tmp
4 -rw-r--r-- 1 grahamellis grahamellis 3 7 Jul 10:04 pod2htmi.tmp
5 -rw-r--r-- 1 grahamellis grahamellis 502 8 Jul 14:28 tick.pm
BirthdayBoy:csr1 grahamellis$


(By the way - the name of my computer today - "BirthdayBoy" - has been allocated to me by the router at the hotel and does not imply anything about the day I was born!)
(written 2008-07-08 18:37:03)

 P214 - Perl - System Dependencies
P258 - Perl - Solaris, OSX and Linux

Back to Training Course and Business Conference Technology

Previous and next or Horse's mouth home

Forward to Perl ... adding to a list - end, middle, start

The Story of Well House Manor
Environment variables in Perl / use Env
Finding operating system settings in Perl
Perl ... adding to a list - end, middle, start
Running operating system commands in Perl
Training Course and Business Conference Technology
FTP server on Fedora Linux
If you are learning Lua, here are some more examples
Dealing with The Press
Sorting in lua - specifying your own sort routine