Unix Perl - Some useful commands.

Here's some useful quick tips in Unix Perl.

1) To see Perl DBI installed and its version  :

perl -e 'use DBI; print $DBI::VERSION,"\n";'

2) To see Perl DBD installed and its version

perl -e 'use DBD::Oracle; print $DBD::Oracle::VERSION,"\n";'

3) Just to Connect to Oracle :

use strict;

use DBI;

my $dbh = DBI->connect('dbi:Oracle:fs1pa_fs1p','<uname>','<passwd>',)|| die "DB conn not made: $DBI::errstr";

$dbh->disconnect;

4) Connect to Oracle and simple Query

use strict;

use DBI;

my $dbh = DBI->connect('dbi:Oracle:fs1pa_fs1p','<uname>','<passwd>',)|| die "DB conn not made: $DBI::errstr";

my $sql = qq{ SELECT TNAME,TABTYPE FROM TAB };

my $sth = $dbh->prepare($sql);

$sth->execute();

my($tname,$tabtype);

$sth->bind_columns(undef, \$tname, \$tabtype);

print "List of Table:\n\n";

while ($sth->fetch() ) {

        print "Object :$tname, Type :$tabtype\n";

}

$sth->finish();

$dbh->disconnect;

5) insert line numbers in a file 

perl -pi -e'$_ = sprintf "%04d %s", $. $_' filename

6) change pattern 'print' to 'printf' and change in same file

perl -e 's/print/printf/g' -p -i  file_name

7) Print no.of lines

perl -le 'open FILE, "file.txt";@_=<FILE>; print $.'

8) just lines 4 to 6

perl -ne 'print if 4 .. 6' file.txt
perl -ne 'print if 4..6' file.txt

 9) Print first column values from line 4 to 6

 perl -F'\|' -lane 'print $F[0] if 4..6' file.txt

10) Avoids the blank lines and print only the lines with contents

perl -ne 'print unless /^$/../^$/' test.txt

 11) Prints only the matching words

perl -lne '/Mukundan/ and print $&' file.txt

12) Prints the entire line

perl -lne '/Mukundan/ and print $_' file.txt

 

13) Get all the PACKAGE objects from oracle

use strict;

use DBI;

my $dbh = DBI->connect('dbi:Oracle:fs1pa_fs1p','<user>','<passwd>',)|| die "DB conn not made: $DBI::errstr";

my $sql = qq{ SELECT OBJECT_NAME FROM USER_OBJECTS WHERE OBJECT_TYPE=? };

my $sth = $dbh->prepare($sql);

$sth->execute("PACKAGE");

my($oname);

$sth->bind_columns(undef, \$oname);

print "List of Packages:\n\n";

 while ($sth->fetch() ) {

        print "Packages :$oname\n";

}

 $sth->finish();

$dbh->disconnect;