using bash command in perl

Question

i have short bash code

cat example.txt | grep mail | awk -F, '{print $1}' | awk -F= '{print $2}'

I want to use it in perl script, and put its output to an array line by line. I tried this but did not work

@array = system('cat /path/example.txt | grep mail | awk -F, {print $1} | awk -F= {print $2}');

Thanks for helping...

This question gives some examples of how to call external programs in Perl. — Nathan Fellman
– Nathan Fellman, Commented May 17, 2011 at 6:24

Rafe Kettler · Accepted Answer · 2011-05-17 14:32:42Z

11

The return value of system() is the return status of the command you executed. If you want the output, use backticks:

@array = `cat /path/example.txt | grep mail | awk -F, {print \$1} | awk -F= {print \$2}`;

When evaluated in list context (e.g. when the return value is assigned to an array), you'll get the lines of output (or an empty list if there's no output).

edited May 17, 2011 at 14:32

answered May 17, 2011 at 6:22

Rafe Kettler

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2 Comments

Konerak Over a year ago

feel free to correct to array, a correct answer is worth more than a funny one. I'll remove the silly comments ;)

ibrahim Over a year ago

I did it but this time awk is not working, it give only output of 'cat /path/example.txt | grep mail' , what should I do?

ADW · Accepted Answer · 2011-05-17 07:02:00Z

8

Try:

@array = `cat /path/example.txt | grep mail | awk -F, {print \$1} | awk -F= {print \$2}')`;

Noting that backticks are used and that the dollar signs need to be escaped as the qx operator will interpolate by default (i.e. it will think that $1 are Perl variables rather than arguments to awk).

answered May 17, 2011 at 7:02

ADW

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1 Comment

J-16 SDiZ Over a year ago

It is safer to use open(); It save some escaping.

TLP · Accepted Answer · 2011-05-17 13:15:20Z

2

Couldn't help making a pure perl version... should work the same, if I remember my very scant awk correctly.

use strict;
use warnings;

open A, '<', '/path/example.txt' or die $!;
my @array = map { (split(/=/,(split(/,/,$_))[0]))[1] . "\n" } (grep /mail/, <A>);

answered May 17, 2011 at 13:15

TLP

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