Perl - Directories

Perl - Directories

Following are the standard functions used to play with directories.

opendir DIRHANDLE, EXPR  # To open a directory

readdir DIRHANDLE        # To read a directory

rewinddir DIRHANDLE      # Positioning pointer to the begining

telldir DIRHANDLE        # Returns current position of the dir

seekdir DIRHANDLE, POS   # Pointing pointer to POS inside dir

closedir DIRHANDLE       # Closing a directory.

Display all the files

There are various ways to list down all the files available in a particular directory. First let's use the simples way to get and list down all the files using glob operator:

#!/usr/bin/perl

# Display all the files in /tmp directory.

$dir = "/tmp/*";

my @files = glob( $dir );

foreach (@files ){

   print $_ . "\n";

}

# Display all the C source files in /tmp directory.

$dir = "/tmp/*.c";

@files = glob( $dir );

foreach (@files ){

   print $_ . "\n";

}

# Display all the hidden files.

$dir = "/tmp/.*";

@files = glob( $dir );

foreach (@files ){

   print $_ . "\n";

}

# Display all the files from /tmp and /home directories.

$dir = "/tmp/* /home/*";

@files = glob( $dir );

foreach (@files ){

   print $_ . "\n";

}

Here is another example which opens a directory and list out all the files available inside this directory.

#!/usr/bin/perl

opendir (DIR, '.') or die "Couldn't open directory, $!";

while ($file = readdir DIR) {

  print "$file\n";

}

closedir DIR;

One more example to print the list of C source files, you might use

#!/usr/bin/perl

opendir(DIR, '.') or die "Couldn't open directory, $!";

foreach (sort grep(/^.*\.c$/,readdir(DIR))){

   print "$_\n";

}

closedir DIR;

Create new directory

You can use mkdir function to create a new directory. You will need to have required permission to create a directory.

#!/usr/bin/perl

$dir = "/tmp/perl";

# This creates perl directory in /tmp directory.

mkdir( $dir ) or die "Couldn't create $dir directory, $!";

print "Directory created successfully\n";

Remove a directory

You can use rmdir function to remove a directory. You will need to have required permission to remove a directory additionally this directory should be empty before you try to remove it.

#!/usr/bin/perl

$dir = "/tmp/perl";

# This removes perl directory from /tmp directory.

rmdir( $dir ) or die "Couldn't remove $dir directory, $!";

print "Directory removed successfully\n";

Change a directory

You can use chdir function to change a directory and go to new location. You will need to have required permission to change a directory and go inside the new directory.

#!/usr/bin/perl

$dir = "/home";

# This changes perl directory  and moves you inside /home directory.

chdir( $dir ) or die "Couldn't go inside $dir directory, $!";

print "Your new location is $dir\n";