Solved

narrowing down a file

Posted on 2011-03-07
6
261 Views
Last Modified: 2012-05-11
I have two files.

File1.txt is tab-separated and contains several fields.
File2.txt contains just one field.

I want to get a subset of file 1, such that field 3 of it matches exactly(1) one of the lines in File2.txt.  

The match has to be complete, not partial (so if one says foxnews.com/blah.html and the other says foxnews.com or vice versa - that would not be a match).  Otherwise, I could have just done grep –F –f File2.txt File1.txt.

How would I do that in a shell script?
0
Comment
Question by:aturetsky
  • 3
  • 2
6 Comments
 
LVL 16

Accepted Solution

by:
sjklein42 earned 300 total points
ID: 35064864
Should work.  Save as "joinIt.pl".

Without any test data, hard to test.  If it doesn't work, please post some test data.

# usage:   perl joinIt.pl infile.txt keyfile.txt

$infile = shift(@ARGV);
$keyfile = shift(@ARGV);

if ( ! open(INFILE, "<$infile") ) { die "*** can't open $infile: $!\n"; }
if ( ! open(KEYFILE, "<$keyfile") ) { die "*** can't open $keyfile: $!\n"; }

while ( <KEYFILE> )
{
	s/[\r\n]//g;
	$key{$_} = 1;
}

while ( <INFILE> )
{
	s/[\r\n]//g;
	@x = split(/\t/);
	if ( $key{$x[2]} ) { print "$_\n"; }
}

Open in new window

0
 
LVL 8

Expert Comment

by:point_pleasant
ID: 35069520
here is a shellscript that should work too, the delimiter in the cut commaned is a tab


for i in `cat file1 | cut -f3 -d'       '`
do
        grep -x $i file2
done
0
 
LVL 1

Author Comment

by:aturetsky
ID: 35072123
thanks, sjklein42 - it worked!

can I ask you - if I wanted to do the exact opposite and get only what's not in the keyfile - what would that look like?
0
Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

 
LVL 1

Author Comment

by:aturetsky
ID: 35072688
actually, I think this might do the job (for that reverse task):


# usage:   perl joinIt.pl infile.txt keyfile.txt

$infile = shift(@ARGV);
$keyfile = shift(@ARGV);

if ( ! open(INFILE, "<$infile") ) { die "*** can't open $infile: $!\n"; }
if ( ! open(KEYFILE, "<$keyfile") ) { die "*** can't open $keyfile: $!\n"; }

while ( <KEYFILE> )
{
       s/[\r\n]//g;
       $key{$_} = 1;
}

while ( <INFILE> )
{
       s/[\r\n]//g;
       @x = split(/\t/);
       if ( not exists($key{$x[2]}) ) { print "$_\n"; }
}
0
 
LVL 8

Expert Comment

by:point_pleasant
ID: 35073184
the shell script to do the reverse would be as follows.  the echo statement is there to seperate each column 3 element from file1

for i in `cat file1 | cut -f3 -d'       '`
do
        echo ================== $i from file1 ======================
        grep -x -v $i file2
done
0
 
LVL 8

Assisted Solution

by:point_pleasant
point_pleasant earned 200 total points
ID: 35073548
sorry didn'd realize you wanted the whole line from file1.  Here is a shell script to do it.  if you want the reverse just add the -v option to grep


while read i
do
        col3=`echo $i | awk '{ print $3 }'`
        found=`grep -x -v $col3 file2`
        if [ "$found" != "" ]
        then
                echo $i
        fi
done < file1
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

The following is a collection of cases for strange behaviour when using advanced techniques in DOS batch files. You should have some basic experience in batch "programming", as I'm assuming some knowledge and not further explain the basics. For some…
Over the years I've spent many an hour playing on hardened, DMZ'd servers, with only a sub-set of the usual GNU toy's to keep me company; frequently I've needed to save and send log or data extracts from these server back to my PC, or to others, and…
Learn several ways to interact with files and get file information from the bash shell. ls lists the contents of a directory: Using the -a flag displays hidden files: Using the -l flag formats the output in a long list: The file command gives us mor…
This Micro Tutorial hows how you can integrate  Mac OSX to a Windows Active Directory Domain. Apple has made it easy to allow users to bind their macs to a windows domain with relative ease. The following video show how to bind OSX Mavericks to …

863 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

26 Experts available now in Live!

Get 1:1 Help Now