concatenate multiple files skipping the first 20 lines in each file

[cbungau]

Hi,

I have to concatenate multiple (500) text files with different number of rows, but skipping the first 20 rows/lines in each file.

I would be very grateful for any suggestions.

Thank you,

Cristian

[Dennis Handly]

If you have a file that contains the list of files and it isn't more than the command line, you can do:
for file in $(< file-list); do
tail -n +19 $file
done > new-file

(You need to use ls to get the files, you can replace $() by something like $(ls *.txt).)

If 500 is too big:
while read file; do
tail -n +19 $file
done < file-list > new-file

[James R. Ferguson · Accepted solution]

Hi Cristian:

One way is:

# cat ./mycat
#!/usr/bin/perl
use strict;
use warnings;
my $OLDARGV = '';
my $lines = 0;
while (<>) {
if ( $OLDARGV ne $ARGV ) {
$OLDARGV = $ARGV;
$lines = 0;
}
$lines++;
next unless $lines > 20;
close ARGV if eof;
print;
}

...run as :

# ./mycat file1 file2 file3... > file.out

Regards!

...JRF...
# ./

[cbungau]

Thank you,

Yours,
Cristian

[cbungau]

Thanks, your suggestions helped.

Also it seems that there is a trim (trim 1.0 version is the latest) package for linux that will remove the first lines from the files and then, cat will do the job.

Cheers,

Cristian