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How to remove a last field from a file

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# 15  
Old 03-07-2010
Hai! U can achieve this using Perl in the following way.
Code:
use strict;
use warnings;

open FH,"<file" or die "Can't open file: $!";
while ( <FH> )
{
    if (s/(\w+)$//g) #matching the last field
    {
        open RFH,">>result_file"; #opening the result file in append mode
        print RFH $`."\n"; #matching all the strings before the pattern. So this will exclude the last field
    }
}

Now the output_file will contain the following contents
Code:
abc def ghi
fgh der
sss ttt uuu vvv kkk

# 16  
Old 03-07-2010
What about:
Code:
awk '{sub(FS$NF,F)}1' infile

# 17  
Old 03-08-2010
This will remove all chars after the last space.
Code:
sed 's/ [^ ]\+$//' nfile

# 18  
Old 03-08-2010
Quote:
Originally Posted by rdcwayx
Code:
awk '{$NF=""}1' urfile

Could you explain how internally it works and i am surprised it's giving same result if replace the number 1 with any number.
# 19  
Old 03-08-2010
Quote:
Originally Posted by danmero
What about:
Code:
awk '{sub(FS$NF,F)}1' infile

danmero your code can be shorten to below with same result:-

Code:
nawk 'sub(FS$NF,"")' infile.txt

SmilieSmilieSmilie

---------- Post updated at 10:24 ---------- Previous update was at 10:09 ----------
Quote:
Originally Posted by thillai_selvan
Hai! U can achieve this using Perl in the following way.
Code:
use strict;
use warnings;

open FH,"<file" or die "Can't open file: $!";
while ( <FH> )
{
    if (s/(\w+)$//g) #matching the last field
    {
        open RFH,">>result_file"; #opening the result file in append mode
        print RFH $`."\n"; #matching all the strings before the pattern. So this will exclude the last field
    }
}

Now the output_file will contain the following contents
Code:
abc def ghi
fgh der
sss ttt uuu vvv kkk

more simple code in perl.

Code:
perl -wlane 'print "@F[0..$#F-1]" ;' infile.txt > outfile.txt

# 20  
Old 03-08-2010
Quote:
Originally Posted by thillai_selvan
Hai! U can achieve this using Perl in the following way.
Code:
use strict;
use warnings;
 
open FH,"<file" or die "Can't open file: $!";
while ( <FH> )
{
    if (s/(\w+)$//g) #matching the last field
    {
        open RFH,">>result_file"; #opening the result file in append mode
        print RFH $`."\n"; #matching all the strings before the pattern. So this will exclude the last field
    }
}

Now the output_file will contain the following contents
Code:
abc def ghi
fgh der
sss ttt uuu vvv kkk

You can make it shorter.

Code:
perl -lane '{$,=" "; pop(@F); print  @F;}' file
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