How to Execute unix commands like "WC, tail, Gunzip, ZIP" against a file which is read from directory

rajsai28 has asked for the wisdom of the Perl Monks concerning the following question:

Hi Monks,

As i mentioned in the title, i need to execute some unix commands on the files which i read from the directory

sub zPrivateSub
{
my $dir = $OUTPUT_DIR;
my $pattern = 'Jun';

opendir( DIR, $dir );

my @files = grep( /$pattern/, readdir(DIR) );
closedir(DIR);

foreach my $file (@files) {
    if ($file=~ m/orig/) {
    my $lcmd = system("wc -l $file");
    }
    else
    {
    print "NO\n";}        
    }
    }
[download]

gives me this error message / faulty output:

orig_file.dat.gz
wc: cannot open orig_file.dat.gz
[download]

please help me on this.

Thanks

Comment on How to Execute unix commands like "WC, tail, Gunzip, ZIP" against a file which is read from directory Select or Download Code

Replies are listed 'Best First'.
Re: How to Execute unix commands like "WC, tail, Gunzip, ZIP" against a file which is read from directory by smls (Friar) on Jun 06, 2013 at 04:37 UTC
You either need to `chdir($dir)` [download] before running the UNIX commands, or pass the full path to them like `system("wc -l $dir/$file")` [download] .	[reply] [d/l] [select]
Re: How to Execute unix commands like "WC, tail, Gunzip, ZIP" against a file which is read from directory by soonix (Chancellor) on Jun 06, 2013 at 05:20 UTC
Alternatively, instead of `system("wc -l $file");` [download] you could do `system("cd $dir; wc -l $file");` [download] which is less efficient, but if instead of wc you have another command, which works in the current directory, this might even be better. Of course, most efficient is chdir before you loop over the files (as suggested by smls)	[reply] [d/l] [select]
Re^2: How to Execute unix commands like "WC, tail, Gunzip, ZIP" against a file which is read from directory by rajsai28 (Novice) on Jun 07, 2013 at 03:10 UTC
Hi Monks, Thanks for your valuable suggestion. i have used the below code and it works for me can we store the value of unix command in some variable because when we execute the unix command it will either return 0 or 1, i want to store the value `chdir($dir); foreach my $file (@files) { if ($file=~ m/orig/) { my $lcmd = system("gunzip -c $file\|tail -1"); }` [download] Output: `123456\|345627899292\|000108418\|` [download] i want to store the value 123456\|345627899292\|000108418\| in variable so that i can use substr to fetch '000108418' Thanks a lot for the valuable inputs thanks & regards,	[reply] [d/l] [select]
Re^3: How to Execute unix commands like "WC, tail, Gunzip, ZIP" against a file which is read from directory by rajsai28 (Novice) on Jun 07, 2013 at 06:16 UTC
Hi Monks, i got the syntax and please check below my $result = `gunzip -c $file\|tail -1`; [download] where i can get the unix command result	[reply] [d/l]
Re^4: How to Execute unix commands like "WC, tail, Gunzip, ZIP" against a file which is read from directory by Corion (Patriarch) on Jun 07, 2013 at 06:21 UTC
Re^5: How to Execute unix commands like "WC, tail, Gunzip, ZIP" against a file which is read from directory by rajsai28 (Novice) on Jun 07, 2013 at 10:02 UTC
Re: How to Execute unix commands like "WC, tail, Gunzip, ZIP" against a file which is read from directory by kcott (Archbishop) on Jun 06, 2013 at 06:32 UTC
Except for some minor rewording, this is the same question you asked a matter of hours ago: "Reading file from the directory". I will be downvoting this node. -- Ken	[reply]
Re^2: How to Execute unix commands like "WC, tail, Gunzip, ZIP" against a file which is read from directory by rajsai28 (Novice) on Jun 07, 2013 at 03:02 UTC
Hi, Yes true, i thought the the question what i asked was not clear so sent by chaning the description and using some format tips. regards,	[reply]