Command Line Dictionary : meaning of

If we have only console, and we want to quickly see meaning of some word. Then we can use following perl script to get dictionary meaning of a word. It uses perl, curl and html2text.
The source code of meaning_of.pl is :

#!/usr/bin/perl -w

## Search the dict.org

use strict;
use warnings;

sub print_usage() 
{
    print STDERR "USAGE: $0 <query>\n";
}

if (@ARGV < 1)
{
    &print_usage();
    exit(-1);
}

my $query = "$ARGV[0]";
$query =~ s/ /\%20/g;

my $cmd = "curl -# -A \"Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)\" -d \"Form=Dict1&Query=${query}&Strategy=*&Database=english\" \"http://www.dict.org/bin/Dict\" | html2text 2>/dev/null";
#system($cmd);
#exit($?);

open(MOFH, "$cmd | ") or die("$0: cannot execute: $cmd\n");

my $skip_lines = 10; # skip first 10 lines
my $line;
while ($line = <MOFH>)
{
    --$skip_lines;
    next if ($skip_lines > 0);
    chomp($line);
    print "$line\n";
}
close(MOFH);

exit(0);

Sample run of above perl script :

$ meaning_of.pl happiness

######################################################################## 100.0%
===============================================================================
4 definitions found for happiness
From The_Collaborative_International_Dictionary_of_English_v.0.48:

  Happiness \Hap"pi*ness\, n. [From Happy.]
     1. Good luck; good fortune; prosperity.
        [1913 Webster]

              All happiness bechance to thee in Milan! --Shak.
        [1913 Webster]

     2. An agreeable feeling or condition of the soul arising from
        good fortune or propitious happening of any kind; the
        possession of those circumstances or that state of being
        which is attended with enjoyment; the state of being
        happy; contentment; joyful satisfaction; felicity;
        blessedness.
        [1913 Webster]

     3. Fortuitous elegance; unstudied grace; -- used especially
        of language.
        [1913 Webster]

              Some beauties yet no precepts can declare,
              For there's a happiness, as well as care. --Pope.

     Syn: Happiness, Felicity, Blessedness, Bliss.

     Usage: Happiness is generic, and is applied to almost every
            kind of enjoyment except that of the animal appetites;
            felicity is a more formal word, and is used more
            sparingly in the same general sense, but with elevated
            associations; blessedness is applied to the most
            refined enjoyment arising from the purest social,
            benevolent, and religious affections; bliss denotes
            still more exalted delight, and is applied more
            appropriately to the joy anticipated in heaven.
            [1913 Webster]

                  O happiness! our being's end and aim! --Pope.
            [1913 Webster]

                  Others in virtue place felicity,
                  But virtue joined with riches and long life;
                  In corporal pleasures he, and careless ease.
                                                    --Milton.
            [1913 Webster]

                  His overthrow heaped happiness upon him;
                  For then, and not till then, he felt himself,
                  And found the blessedness of being little.
                                                    --Shak.
            [1913 Webster]
From WordNet_(r)_3.0_(2006):

  happiness
      n 1: state of well-being characterized by emotions ranging from
           contentment to intense joy [syn: happiness, felicity]
           [ant: unhappiness]
      2: emotions experienced when in a state of well-being [ant:
         sadness, unhappiness]
From Moby_Thesaurus_II_by_Grady_Ward,_1.0:

  117 Moby Thesaurus words for "happiness":
     Easy Street, acceptance, affluence, appropriateness, beatification,
     beatitude, becomingness, bed of roses, bewitchment, blessedness,
     bliss, blissfulness, blitheness, blithesomeness, brightness, cheer,
     cheerfulness, cheeriness, cheery vein, civility, cloud nine,
     clover, comfort, composure, content, contentedness, contentment,
     decency, decorousness, decorum, delectation, delight, ease,
     easy circumstances, ecstasy, ecstatics, elation, enchantment,
     enjoyment, entire satisfaction, eupeptic mien, euphoria,
     exaltation, exhilaration, exuberance, felicity, fitness,
     fittingness, fleshpots, fulfillment, gaiety, geniality,
     genteelness, gentility, gladness, gladsomeness, glee, good cheer,
     gracious life, gracious living, heaven, high spirits, hopefulness,
     intoxication, jollity, joy, joyance, joyfulness, joyousness,
     jubilation, lap of luxury, life of ease, loaves and fishes, luxury,
     meetness, optimism, overhappiness, overjoyfulness, paradise,
     peace of mind, pleasantness, pleasure, properness, propriety,
     prosperity, prosperousness, radiance, rapture, ravishment,
     reconcilement, reconciliation, resignation, rightness,
     rosy expectation, sanguine humor, sanguineness, satisfaction,
     security, seemliness, seventh heaven, success, suitability,
     sunniness, sunshine, the affluent life, the good life,
     thriving condition, transport, unalloyed happiness,
     upward mobility, urbanity, velvet, weal, wealth, welfare,
     well-being, winsomeness


From The_Devil's_Dictionary_(1881-1906):

  HAPPINESS, n.  An agreeable sensation arising from contemplating the
  misery of another.

===============================================================================
      Questions or comments about this site? Contact webmaster@dict.org

Mount/Unmount USB pendrive/USB Harddisk

We have seen sometimes automounting of external drives(USB Pendrive/USB harddisk) work and sometimes it simply does not work. The pain increase when there are multiple partitions in the external drive. To resolve this issue, I have written a perl script to mount/unmount multiple partitions.

The following perl script is useful in following cases:
1. Mounting/Unmounting(-u flag for unmounting) partitions in external drives.
2. Mounting/Unmounting partitions of internal drives too (-d , to (mount to)/(unmount from) any specific location).
3. This script also recognizes single vfat(FAT32) partition(When filesystem was created across the entire device: please refer mkfs.vfat -I) pen-drive too.
4. Others (if you find anything else, please comment :) )

#!/usr/bin/perl -w
#===============================================================================
#
#         FILE:  mount_usb_disks.pl
#
#        USAGE:  ./mount_usb_disks.pl 
#
#  DESCRIPTION:  Mount USB disks or pendrive
#
#      OPTIONS:  ---
# REQUIREMENTS:  ---
#         BUGS:  ---
#        NOTES:  ---
#       AUTHOR:  Mitesh Singh Jat (mitesh), <mitesh[at]yahoo-inc[dot]com>
#      COMPANY:  Yahoo Inc, India
#      VERSION:  1.0
#      CREATED:  02/22/2012 05:37:54 PM IST
#     REVISION:  ---
#===============================================================================

use strict;
use warnings;

use Getopt::Std;
my $mount_point_base = "/mnt/usb_disks";
my $umount = 0;

sub usage()
{
    print STDERR "USAGE: $0 [options] \n";
    print STDERR "          -d <mount_base_dir>     mount point dir: default  $mount_point_base\n";
    print STDERR "          -u                      unmount \n";
}

sub run_cmd()
{
    my $cmd = $_[0];
    print "Running: $cmd\n";
    system("$cmd");
    my $retval = $?;
    if ($retval < 0)
    {
        print STDERR "Error in running: $cmd\n$retval\n";
    }
    return ($retval);
}

sub run_cmd_get()
{
    my $cmd = $_[0];
    print "Running: $cmd\n";
    my @outs = `$cmd`;
    my $retval = $?;
    if ($retval < 0)
    {
        print STDERR "Error in running: $cmd\n$retval\n";
        exit($retval);
    }
    chomp(@outs);
    return (@outs);
}

my %opts;
getopt('d:', \%opts);

foreach my $opt (sort keys %opts)
{
    if (!defined($opts{$opt}))
    {   
        print STDERR "$0: Requires value for option '$opt'\n";
        &usage();
        exit(-1);
    }   
}
if (defined($opts{"d"}))
{
    $mount_point_base = $opts{"d"};
}
if (defined($opts{"u"}))
{
    $umount = 1;
}

my $retval = 0;
my $cmd;
$retval = `whoami`;
chomp($retval);
unless ($retval eq "root")
{
    print STDERR "$0: Please run this script as 'root' user.\n";
    &usage();
    exit(-1);
}
unless ($umount)
{
    print "Mounting on $mount_point_base\n";
    unless (-d "$mount_point_base") 
    {
        $retval = &run_cmd("mkdir -p $mount_point_base");
        exit($retval) if ($retval < 0);
    }

    my @temps = &run_cmd_get("mount | awk '{print \$1}' | grep \"^/dev/\"");
    my %mounted_devs;
    foreach my $temp (@temps)
    {
        $mounted_devs{$temp} = 1;
        $temp =~ s/\/sd([a-z]).*/\/sd$1/;
        $mounted_devs{$temp}++;
    }
    ## Take care of swap
    @temps = &run_cmd_get("cat /proc/swaps | awk '{print \$1}' | grep \"^/dev/\"");
    foreach my $temp (@temps)
    {
        $mounted_devs{$temp} = 1;
        $temp =~ s/\/sd([a-z]).*/\/sd$1/;
        $mounted_devs{$temp}++;
    }
    my %unmounted_devs;
    my $total = 0;
    @temps = &run_cmd_get("ls /dev/sd*");
    foreach my $temp (@temps)
    {
        next if (defined($mounted_devs{$temp}));
        ## Take care of logical partition, which cannot be mounted
        my @outs = &run_cmd_get("fdisk -s $temp");
        $retval = $outs[0];
        next if ($retval <= 1);      
        $unmounted_devs{$temp} = 1;
        $temp =~ s/\/sd([a-z]).*/\/sd$1/;
        if (defined($unmounted_devs{$temp}))
        {
            delete($unmounted_devs{$temp});
            $total--;
        }
        $total++;
    }
    if ($total == 0)
    {
        print "$0: No partition to mount.\nexiting...\n";
        exit(0);
    }

    print "\n--------------------------------------------\n";
    print "Following partitions are not mounted...\n";
    print "--------------------------------------------\n";
    foreach my $temp (sort keys %unmounted_devs) 
    {
        print "$temp\n";
    }
    print "--------------------------------------------\n";

    ## Now we can mount these
    foreach my $temp (sort keys %unmounted_devs)
    {
        my $mount_dir = $temp;
        $mount_dir =~ s/^\/dev\//$mount_point_base\//;
        print "Mounting $temp -> $mount_dir\n";
        unless (-d "$mount_dir")
        {
            $retval = &run_cmd("mkdir -p $mount_dir");
            exit($retval) if ($retval < 0);
        }

        $cmd = "mount $temp $mount_dir";
        $retval = &run_cmd("$cmd");
        if ($retval < 0)
        {
            print STDERR "!!!Cannot mount $temp on $mount_dir\n";
        }
    }
}
else
{
    unless ($mount_point_base =~ m/^\//) 
    {
        $retval = `pwd`;
        chomp($retval);
        $mount_point_base = "$retval/$mount_point_base";
    }
    print "Unmounting from $mount_point_base\n";
    $cmd = "mount | awk -F \" on \" '{print \$2}' | awk -F \" type \" '{print \$1}' | grep \"$mount_point_base\"";
    my @temps = &run_cmd_get("$cmd");
    if (@temps == 0)
    {
        print "$0: No partition to unmount.\nexiting...\n";
        exit(0);
    }
    print "\n--------------------------------------------\n";
    print "Following directories are mounted...\n";
    print "--------------------------------------------\n";
    foreach my $temp (@temps)
    {
        print "$temp\n";
    }
    print "--------------------------------------------\n";

    foreach my $temp (@temps)
    {
        $cmd = "umount $temp";
        $retval = &run_cmd("$cmd");
        if ($retval < 0)
        {
            print STDERR "!!!Cannot umount $temp\n";
        }
        else
        {
            &run_cmd("rmdir $temp");       # delete dir if empty
        }
    }
}
exit(0);

Video Cutter V2: Video Cutting Using Mencoder

I have upgraded the Video Cutter program. Now it has 2 more features:
1. Strict Mode (-s flag): In this mode, strict monotonously increasing order of times must be given in the configuration (default: video_cutter.conf) file.
2. Joining Split Videos (-j flag): When this flag is given with the command, it does join the split video files into a single video file.

Here is the updated version of the earlier perl script:

#!/usr/bin/perl -w
#===============================================================================
#
#         FILE:  video_cutter.pl
#
#        USAGE:  ./video_cutter.pl [options] <input_video_file>
#
#  DESCRIPTION:  
#
#      OPTIONS:  ---
# REQUIREMENTS:  ---
#         BUGS:  ---
#        NOTES:  ---
#       AUTHOR:  Mitesh Singh Jat (mitesh), <mitesh[at]yahoo-inc[dot]com>
#      VERSION:  2.0
#      CREATED:  02/12/2011 03:57:55 PM IST
#===============================================================================

use strict;
use warnings;

use Getopt::Std;

sub usage()
{
    print STDERR "USAGE: $0 [options] <input_video_file>\n";
    print STDERR "          -c <conf_file>    default  /base_dir/input_video_file/video_cutter.conf\n";
    print STDERR "                            Start_time(hh:mm:ss),End_time(hh:mm:ss)\n\n";
    print STDERR "          -o <out_dir>      default  /base_dir/input_video_file/\n";
    print STDERR "          -s                strict format check for conf files     [default: no checking]\n";
    print STDERR "          -j                Join output splits into one video file [default: no joining]\n";
}

sub hms_to_seconds()
{
    my $end_sec = 0;
    my ($h, $m, $s) = split(/:/, $_[0]);
    $s = defined($s) ? $s : 0;
    $end_sec += $s;
    $m = defined($m) ? $m : 0;
    $end_sec += (60 * $m);
    $h = defined($h) ? $h : 0;
    $end_sec += (60 * 60 * $h);
    return($end_sec);
}

sub check_times_in_file()
{
    my $conf_file = $_[0];
    open(FH, "$conf_file") or die("$0: Cannot open '$conf_file'\n");
    my $line;
    my $nline = 0;
    my $prev_end_sec = -1;
    while ($line = <FH>)
    {
        chomp($line);
        ++$nline;
        next if ($line =~ m/^#/);
        my ($start_time, $end_time) = split(/,/, $line);
        if (!defined($end_time))
        {
            print STDERR "$0: End time(HH:MM:SS) is not present in line no $nline: $line\n";
            close(CFH);
            return;
        }
        my ($h, $m, $s) = split(/:/, $start_time);
        if (!defined($s))
        {
            print STDERR "$0: Start time is not in format (HH:MM:SS) line no $nline: $line\n";
            close(CFH);
            return;
        }
        ($h, $m, $s) = split(/:/, $end_time);
        if (!defined($s))
        {
            print STDERR "$0: End time is not in format (HH:MM:SS) line no $nline: $line\n";
            close(CFH);
            return;
        }

        my $start_sec = &hms_to_seconds($start_time);
        my $end_sec = &hms_to_seconds($end_time);
        if ($start_sec >= $end_sec)
        {
            print STDERR "$0: $start_sec >= $end_sec in line no $nline: $line\n";
            close(CFH);
            return;
        }
        if ($prev_end_sec >= $start_sec)
        {
            print STDERR "$0: $prev_end_sec >= $start_sec in line no $nline: $line and prev line\n";
            close(CFH);
            return;
        }
        $prev_end_sec = $end_sec;
    }
    close(FH);
    return ($nline);
}

my %opts;
getopt('o:c:', \%opts);

foreach my $opt (sort keys %opts)
{
    if (!defined($opts{$opt}))
    {
        print STDERR "$0: Requires value for option '$opt'\n";
        &usage();
        exit(-1);
    }
}

if (@ARGV != 1)
{
    &usage();
    exit(-1);
}

my $input_video_file = "$ARGV[0]";
my $out_dir = `dirname $input_video_file`;
chomp($out_dir);
my $conf_file = "$out_dir/video_cutter.conf";
my $strict_checking = 0;
my $join_outputs = 0;
my $out_video_files = "";

if (defined($opts{"c"}))
{
    $conf_file = $opts{"c"};
}
if (defined($opts{"o"}))
{
    $out_dir = $opts{"o"};
}
if (defined($opts{"s"}))
{
    $strict_checking = 1;
}
if (defined($opts{"j"}))
{
    $join_outputs = 1;
}

unless (-f "$input_video_file")
{
    print STDERR "$0: Input video file '$input_video_file' is not present\n";
    exit(-1);
}
unless (-f "$conf_file")
{
    print STDERR "$0: split conf file '$conf_file' is not present\n";
    exit(-1);
}
unless (-d "$out_dir")
{
    print STDERR "$0: out dir '$out_dir' is not present\n";
    exit(-1);
}
unless (-w "$out_dir")
{
    print STDERR "$0: out dir '$out_dir' is not writable\n";
    exit(-1);
}

my $mencoder = "/usr/local/bin/mencoder";
unless (-x $mencoder)
{
    $mencoder = "/usr/bin/mencoder";
}
unless (-x $mencoder)
{
    print STDERR "$0: please install mencoder\n";
    print STDERR "sudo apt-get install mencoder\n";
    exit(-1);
}

open(CFH, "$conf_file") or die("$0: Cannot open '$conf_file'\n");
my $line;
my $nline = 0;
my $nsplit = 0;
my $split_name = `basename $input_video_file`;
chomp($split_name);
$split_name =~ s/\.[^.]*$//;
my $split_ext = $input_video_file;
$split_ext =~ s/.*\.([^.]*)$/$1/;
my $success = 0;

if ($strict_checking == 1)
{
    print "Strict Mode\n";
    my $retval = &check_times_in_file($conf_file);
    if (!defined($retval))
    {
        print STDERR "$0: Problem in conf file \"$conf_file\"\n";
        exit(-1);
    }
}
while ($line = <CFH>)
{
    chomp($line);
    $nline++;
    next if ($line =~ m/^#/);
    my ($start_time, $end_time) = split(/,/, $line);
    next if (!defined($end_time));
    my $start_sec = &hms_to_seconds($start_time);
    my $end_sec = &hms_to_seconds($end_time);
    if ($start_sec >= $end_sec)
    {
        print STDERR "$0: $start_sec >= $end_sec\n";
        print STDERR "    $start_time >= $end_time ... skipping for line no $nline ...\n";
        next;
    }
    $end_sec -= $start_sec;
    my $cmd = sprintf("%s -ss %d -endpos %d -ovc copy -oac copy -o %s/%s_%03d.%s %s", 
            $mencoder, $start_sec, $end_sec, $out_dir, $split_name, $nsplit,
            $split_ext, $input_video_file);
    print "\n\n";
    print "-" x 80 . "\n";;
    print "$cmd\n";
    system("$cmd");
    if ($? != 0)
    {
        print STDERR "$0: failed to create $nsplit split for line no $nline\n";
        print STDERR "\t$cmd\n";
    }
    else
    {
        print STDOUT "Created $nsplit split for line $nline\n";
        $out_video_files .= sprintf(" %s/%s_%03d.%s", $out_dir, $split_name, $nsplit, $split_ext);
        $success++;
    }
    print "-" x 80 . "\n";;
    $nsplit++;
}

close(CFH);

print "\n";
print "=" x 80 . "\n";;
printf("Total lines = %d,   Success = %d/%d,  Failure = %d/%d\n",
        $nline, $success, $nsplit,
        $nsplit - $success, $nsplit);
print "=" x 80 . "\n";;

if ($join_outputs == 1)
{
    if ($success < 1)
    {
        print STDERR "$0: failed to join video files.\n";
        exit(-1);
    }
    my $joined_video_file = sprintf("%s/%s_joined.%s", $out_dir, $split_name, $split_ext);
    my $cmd = sprintf("%s -ovc copy -oac copy -o %s %s", 
            $mencoder, $joined_video_file, $out_video_files);
    print "\n\n";
    print "-" x 80 . "\n";;
    print "Joining Video Files into $joined_video_file\n";
    print "-" x 80 . "\n";;
    print "$cmd\n";
    system("$cmd");
    if ($? != 0)
    {
        print STDERR "$0: failed to create joined video file $joined_video_file\n";
        print STDERR "\t$cmd\n";
    }
    else
    {
        print STDOUT "Created joined video file $joined_video_file\n";
    }
    print "-" x 80 . "\n";;
}

exit(0);

Video Cutter: Video Cutting using Mencoder

I have written a perl script, then can split/cut parts from a video file.

#!/usr/bin/perl -w
#===============================================================================
#
#         FILE:  video_cutter.pl
#
#        USAGE:  ./video_cutter.pl [options] <input_video_file>
#
#  DESCRIPTION:  
#
#      OPTIONS:  ---
# REQUIREMENTS:  ---
#         BUGS:  ---
#        NOTES:  ---
#       AUTHOR:  Mitesh Singh Jat (mitesh), <mitesh[at]yahoo-inc[dot]com>
#      VERSION:  1.0
#      CREATED:  06/26/2011 03:57:55 PM IST
#     REVISION:  ---
#===============================================================================

use strict;
use warnings;

use Getopt::Std;

sub usage()
{
   print STDERR "USAGE: $0 [options] <input_video_file>\n";
   print STDERR "          -c <conf_file>    default  /base_dir/input_video_file/video_cutter.conf\n";
   print STDERR "                            Start_time(hh:mm:ss),End_time(hh:mm:ss)\n\n";
   print STDERR "          -o <out_dir>      default  /base_dir/input_video_file/\n";
}

sub hms_to_seconds()
{
   my $end_sec = 0;
   my ($h, $m, $s) = split(/:/, $_[0]);
   $s = defined($s) ? $s : 0;
   $end_sec += $s;
   $m = defined($m) ? $m : 0;
   $end_sec += (60 * $m);
   $h = defined($h) ? $h : 0;
   $end_sec += (3600 * $h);
   return($end_sec);
}

my %opts;
getopt('o:c:', \%opts);

foreach my $opt (sort keys %opts)
{
   if (!defined($opts{$opt}))
   {
       print STDERR "$0: Requires value for option '$opt'\n";
       &usage();
       exit(-1);
   }
}

if (@ARGV != 1)
{
   &usage();
   exit(-1);
}

my $input_video_file = "$ARGV[0]";
my $out_dir = `dirname $input_video_file`;
chomp($out_dir);
my $conf_file = "$out_dir/video_cutter.conf";

if (defined($opts{"c"}))
{
   $conf_file = $opts{"c"};
}
if (defined($opts{"o"}))
{
   $out_dir = $opts{"o"};
}

unless (-f "$input_video_file")
{
   print STDERR "$0: Input video file '$input_video_file' is not present\n";
   exit(-1);
}
unless (-f "$conf_file")
{
   print STDERR "$0: split conf file '$conf_file' is not present\n";
   exit(-1);
}
unless (-d "$out_dir")
{
   print STDERR "$0: out dir '$out_dir' is not present\n";
   exit(-1);
}
unless (-w "$out_dir")
{
   print STDERR "$0: out dir '$out_dir' is not writable\n";
   exit(-1);
}

my $mencoder = "/usr/local/bin/mencoder";
unless (-x $mencoder)
{
   $mencoder = "/usr/bin/mencoder";
}
unless (-x $mencoder)
{
   print STDERR "$0: please install mencoder\n";
   print STDERR "sudo apt-get install mencoder\n";
   exit(-1);
}

open(CFH, "$conf_file") or die("$0: Cannot open '$conf_file'\n");
my $line;
my $nline = 0;
my $nsplit = 0;
my $split_name = `basename $input_video_file`;
chomp($split_name);
$split_name =~ s/\.[^.]*$//;
my $split_ext = $input_video_file;
$split_ext =~ s/.*\.([^.]*)$/$1/;
my $success = 0;
while ($line = <CFH>)
{
   chomp($line);
   $nline++;
   next if ($line =~ m/^#/);
   my ($start_time, $end_time) = split(/,/, $line);
   next if (!defined($end_time));
   my $start_sec = &hms_to_seconds($start_time);
   my $end_sec = &hms_to_seconds($end_time);
   if ($start_sec >= $end_sec)
   {
       print STDERR "$0: $start_sec >= $end_sec\n";
       print STDERR "    $start_time >= $end_time ... skipping for line no $nline ...\n";
       next;
   }
   $end_sec -= $start_sec;
   my $cmd = sprintf("%s -ss %d -endpos %d -ovc copy -oac copy -o %s/%s_%03d.%s %s",
           $mencoder, $start_sec, $end_sec, $out_dir, $split_name, $nsplit,
           $split_ext, $input_video_file);
   print "\n\n";
   print "-" x 80 . "\n";;
   print "$cmd\n";
   system("$cmd");
   if ($? != 0)
   {
       print STDERR "$0: failed to create $nsplit split for line no $nline\n";
       print STDERR "\t$cmd\n";
   }
   else
   {
       print STDOUT "Created $nsplit split for line $nline\n";
       $success++;
   }
   print "-" x 80 . "\n";;
   $nsplit++;
}

close(CFH);

print "\n";
print "=" x 80 . "\n";;
printf("Total lines = %d,   Success = %d/%d,  Failure = %d/%d\n",
       $nline, $success, $nsplit,
       $nsplit - $success, $nsplit);
print "=" x 80 . "\n";;

exit(0);

Please place the above perl script (video_cutter.pl) in any directory present in $PATH.


Sample Run:


Usage of the above script.

$ video_cutter.pl 
USAGE: /home/mitesh/Programming/Perl/WCS/video_cutter.pl [options] 
         -c     default  /base_dir/input_video_file/video_cutter.conf
                           Start_time(hh:mm:ss),End_time(hh:mm:ss)

         -o       default  /base_dir/input_video_file/

Content of a sample config file, specifying the split timings.
This will create 3 splits, of 0s-90s, 140s-210s, and 240s-End.

$ cat test_video.conf 
00:00:00,00:01:30
00:02:20,00:03:30
00:04:00,59:59:00

Now, it will create the three split files in ~/Video/test/ directory.

$ video_cutter.pl -c test_video.conf -o ~/Video/test test_video.vob 


--------------------------------------------------------------------------------
/usr/local/bin/mencoder -ss 0 -endpos 90 -ovc copy -oac copy -o /home/mitesh/Video/test/test_video_000.vob test_video.vob
MEncoder 1.0rc4-4.4.5 (C) 2000-2010 MPlayer Team
...
...
...
Created 2 split for line 3
--------------------------------------------------------------------------------

================================================================================
Total lines = 3,   Success = 3/3,  Failure = 0/3
================================================================================
$ ls -l ~/Video/test/*.vob
-rw-r--r-- 1 mitesh mitesh   7519672 Jun 27 00:31 /home/mitesh/Video/test/test_video_000.vob
-rw-r--r-- 1 mitesh mitesh   5844598 Jun 27 00:31 /home/mitesh/Video/test/test_video_001.vob
-rw-r--r-- 1 mitesh mitesh 570855360 Jun 27 00:30 /home/mitesh/Video/test/test_video_002.vob

CPU Frequency Scaling

I have written a small shell script to increase or decrease CPU frequency. By default, it shows current CPU Frequency Scaling Governor. This can be changed only by root user. So this script needs to be run as root user or sudo as root, while changing the CPU Frequency Scaling governor.

#!/bin/bash

available_governors=$(cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_available_governors \
            | head -1 | sed -e 's/ \([a-zA-Z0-9]\)/|\1/g' -e 's/ $//')
if [ $# -ne 1 ]
then
  
   echo "USAGE: $0 [$available_governors]"
fi

echo "Command line to change CPU Scaling."
echo "                    - By Mitesh Singh Jat"
echo ""

## CPU Governor path
#/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
function current_cpu_governor ()
{
   echo -n "Current CPU Scaling Governor is: "
   cpu_scaling_governor="NOT SET"
   for governor in $(ls /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor)
   do
       cpu_scaling_governor=$(cat $governor)
   done
   echo "$cpu_scaling_governor"
}

current_cpu_governor;

## Exit, if no governor is provided
new_governor=""
if [ $# -eq 0 ]
then
   exit 0
else
   new_governor="$1"
fi

## Run as root always
user_id=`whoami`
if [[ "$user_id" != "root" ]]
then
   echo "$0: please run this script as root user."
   exit
fi 

if [ -z $(echo $available_governors | sed -e 's/^/|/' -e 's/$/|/' | grep "|$new_governor|") ]
then
   echo "Sorry, this mode '$new_governor' is not supported."
   exit 1
else
   echo "Setting CPU into '$new_governor' Mode..."
fi
## Now set cpu governor to the given mode
for governor in $(ls /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor)
do
   echo "$new_governor" > $governor
done
current_cpu_governor;

exit 0

Sample Run

Getting current CPU Frequency Scaling Governor
$ cd /path/where/cpu_scaling.sh/is/copied/
$ ./cpu_scaling.sh
USAGE: ./cpu_scaling.sh [powersave|conservative|ondemand|userspace|performance]
Command line to change CPU Scaling.
                   - By Mitesh Singh Jat

Current CPU Scaling Governor is: ondemand


Increasing CPU frequency (Please run as root).
$ ./cpu_scaling.sh performance
Command line to change CPU Scaling.
                   - By Mitesh Singh Jat

Current CPU Scaling Governor is: ondemand
./cpu_scaling.sh: please run this script as root user.
$ sudo ./cpu_scaling.sh performance
[sudo] password for mitesh:
Command line to change CPU Scaling.
                   - By Mitesh Singh Jat

Current CPU Scaling Governor is: ondemand
Setting CPU into Performance Mode...
Current CPU Scaling Governor is: performance
$ ./cpu_scaling.sh
USAGE: ./cpu_scaling.sh [powersave|conservative|ondemand|userspace|performance]
Command line to change CPU Scaling.
                   - By Mitesh Singh Jat

Current CPU Scaling Governor is: performance


Decreasing CPU frequency
$ sudo ./cpu_scaling.sh ondemand
Command line to change CPU Scaling.
                   - By Mitesh Singh Jat

Current CPU Scaling Governor is: performance
Setting CPU into OnDemand Mode...
Current CPU Scaling Governor is: ondemand

Playing only Audio from a Video File

If you want to play only audio from a video file (say xyz.avi),
please provide -vo null in mplayer, given as:

$ mplayer -vo null xyz.avi


Speeding up Disk Performance

We can increase Hard Disk performance by ~40%, and decrease power consumption by Hard Disk, if we provide "noatime,nodiratime" options during partition mounting. Actually what happens is: whenever a file/directory is accessed, its atime "access time" is updated with epoch. These two options prevent these not-so-useful disk accesses. Hence
performance improvement.



The sample mount point (/home) entry in /etc/fstab may look like:

$ cat /etc/fstab | grep home
/dev/sda2 /home ext3 defaults,noatime,nodiratime 0 0