awk usage in perl scripting

Question

Hi am writing a script which its need to grep the 6th column of the output using awk command but am getting other output. What is the exact syntax in perl to extract 6th column using awk?

#!/usr/bin/perl
use strict;
use warnings;
use diagnostics;
my $filesystem=`df -h |grep -i dev|grep -vE '^Filesystem|proc|none|udev|tmpfs'`;
print "(\"$filesystem\"|awk '{print \$6}')"

Output :
7831c1c4be8c% ./test.pl
("/dev/disk1     112Gi   43Gi   69Gi    39% 11227595 18084674   38%   /
devfs          183Ki  183Ki    0Bi   100%      634        0  100%   /dev
"|awk '{print  $6}')%

Am trying to remove the % how it can be done ?

7831c1c4be8c% cat test.pl
#!/usr/bin/perl
use warnings;
use strict;

open my $FS, q(df -h |) or die $!;
while (<$FS>) {
print +(split)[4], "\n"
    if /dev/i and not /devfs/;
 }
 7831c1c4be8c% ./test.pl
 40%

Give us some input data and what you like from it. I guess it would be possible to solve this using so only grep or awk — Jotne
– Jotne, Commented Mar 28, 2015 at 18:27

mpapec · Accepted Answer · 2015-03-29 10:43:42Z

4

You don't need awk inside Perl.

#!/usr/bin/perl
use warnings;
use strict;

open my $FS, '-|', q(df -h) or die $!;
while (<$FS>) {
    print +(split)[5], "\n"
        if /dev/i and not /^Filesystem|proc|none|udev|tmpfs/;
}

edited Mar 29, 2015 at 10:43

mpapec

50.7k8 gold badges71 silver badges133 bronze badges

answered Mar 28, 2015 at 18:30

choroba

245k27 gold badges221 silver badges304 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Tom Fenech Over a year ago

Nor do you need grep for that matter (and I'm sure there's an alternative to using df :)

choroba Over a year ago

@TomFenech: Working on it :)

beasy · Accepted Answer · 2015-07-29 12:50:19Z

1

as the previous answer says, you don't need awk or grep system calls in perl. however, I will tell you that one reason your code isn't working is because you never made the awk system call. print does not execute the system call. you would have to use system() to execute it.

anyway fwiw you can also do what you want in a one-liner like so:

df -h | perl -lnae 'next if $F[0] =~ /regex/; print $F[5]'

edited Jul 29, 2015 at 12:50

answered Mar 28, 2015 at 20:14

beasy

1,2319 silver badges16 bronze badges

2 Comments

user000001 Over a year ago

Why echo "$(df -h)" | ... and not just df -h | ... ?

beasy Over a year ago

@user000001 ha you're right. echo is totally unnecessary. as you can tell I use perl alone a lot more than bash

Collectives™ on Stack Overflow

awk usage in perl scripting

2 Answers 2

2 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related