[Linux][Shell] Cleaning PATH environment variable.

With using terminal for a long time, PATH variable tends to be longer and longer due to duplicated path.
Here is simple sample script – with Perl – to resolve this.

# remove duplication at give PATH-format-string
unique_path() {
perl -w -e '
    my %path_hash;
    exit unless (defined $ARGV[0]);
    foreach $p (split (/\:/, $ARGV[0])) {
        unless (defined $path_hash{$p}) {
            $path_hash{$p} = 1;
            push @newpath, $p;
    print join ":", @newpath;
' $1
PATH=$(unique_path "$PATH")

Done :-).