Shell Programming and Scripting

$ date
Sat Jan 11 14:12:06 EDT 2014
$cat sample.txt
10-10-2013 09:00:01 AM|Line test 1234567
16-10-2013 08:30:00 AM|Line test 2345567
25-10-2013 07:30:00 AM|Line test 3456678
26-10-2013 06:00:00 AM|Line test 4567890
28-10-2013 07:30:00 AM|Line test 5678910
15-12-2013 10:00:00 PM|Line test 7891234
10-01-2014 03:00:00 PM|Line test 8901234

$cat sample1.txt
15-12-2013 10:00:00 PM|Line test 7891234
10-01-2014 03:00:00 PM|Line test 8901234

uname -a

#!/usr/bin/ksh
#
# -- script to remove lines from a file
# -- older than the given number of days
# -- based on the date in column 1
#

# check command line for given number of days
if [ $# -ne 2 ]
then
    echo "Usage: $0 </path/to/file> <number of days>"
    exit 1
fi

# store file and number of days
f=$1
d=$2

# get the current date in seconds past epoch
c=$(date +%s)

# new file
n="$f.new"

# read file line by line, convert the date in
# column one to seconds pase epoch and check if
# older than the given number of days
while read line
do
    c1=$(echo $line | awk '{print $1}')
    f1=$(echo "$c1" | awk '{gsub(/-/," ",$0)}{print $3" "$2" "$1}')
    secs=$(perl -e 'use Time::Local; print timelocal(0,0,0,$ARGV[2], $ARGV[1]-1, $ARGV[0]);' $f1)
    dif=$(echo "scale=0; ($c - $secs) / (24*3600)" | bc)
    if [ $dif -le $d ]
    then
        echo $line >> $n
    fi
done < $f

# remove backup original file and rename new file
mv $f $f.ORIG
mv $n $f
cat $f

# done
exit 0

./remoldlines.ksh
Usage: ./remoldlines.ksh </path/to/file> <number of days>

./remOldLines.ksh /tmp/file.txt 30
15-12-2013 10:00:00 PM|Line test 7891234
10-01-2014 03:00:00 PM|Line test 8901234

$ cat remoldlines.pl
#!/usr/bin/env perl
use Time::Local;

while (my $ln = <STDIN>) {
    my ($d, $mt, $y, $h, $m, $s, $pm) = split(/[ :-]/, $ln);
    $h += 12 unless ($pm != "PM");
    my $age = time() - timelocal($s,$m,$h,$d,$mt-1,$y);
    print $ln unless ($age > int($ARGV[0])*3600*24);
}

$ remoldlines.pl 30 < sample.txt
20-12-2013 10:00:00 PM|Line test 7891234
15-01-2014 03:00:00 PM|Line test 8901234

#!/usr/bin/env python

import sys
from time import mktime,strptime 
from datetime import datetime

now  = datetime.now()
with open('sample.txt','rb') as f:
    for line in f:
        L = line.split('|')
        before = datetime.fromtimestamp(
                 mktime(strptime(L[0],'%d-%m-%Y %I:%M:%S %p')))
        old = now - before
        if  old.days < 30:
            sys.stdout.write(line)