[root@ns7 tmp]# cat folk.pl
#!/usr/bin/perl

$pid = fork();
if( $pid == 0 ){
print "This is child process\n";
print "Chile process is existing\n";
exit 0;
}
print "This is parent process and child ID is $pid\n";
print "Parent process is existing\n";
exit 0;

#This will produce following result



#This is parent process and child ID is 16417
#Parent process is existing
#This is child process
#Chile process is existing

[root@ns7 bin]# ls -al |grep perl
-rwxr-xr-x 1 root root 24106 Apr 3 2009 find2perl
-rwxr-xr-x 2 root root 14836 Apr 3 2009 perl
-rwxr-xr-x 2 root root 14836 Apr 3 2009 perl5.8.8
-rwxr-xr-x 1 root root 36840 Apr 3 2009 perlbug
-rwxr-xr-x 1 root root 17953 Apr 3 2009 perlcc
-rwxr-xr-x 1 root root 224 Apr 3 2009 perldoc
-rwxr-xr-x 1 root root 11937 Apr 3 2009 perlivp
[root@ns7 bin]# chmod 700 /usr/bin/perl
[root@ns7 bin]# ls -al |grep perl
-rwxr-xr-x 1 root root 24106 Apr 3 2009 find2perl
-rwx------ 2 root root 14836 Apr 3 2009 perl
-rwx------ 2 root root 14836 Apr 3 2009 perl5.8.8
-rwxr-xr-x 1 root root 36840 Apr 3 2009 perlbug
-rwxr-xr-x 1 root root 17953 Apr 3 2009 perlcc
-rwxr-xr-x 1 root root 224 Apr 3 2009 perldoc
-rwxr-xr-x 1 root root 11937 Apr 3 2009 perlivp

[root@ns7 ~]# ls -al /usr/bin/perl
-rwx------ 2 root root 14836 Apr 3 2009 /usr/bin/perl
[root@ns7 ~]# chmod 755 /usr/bin/perl
[root@ns7 ~]# ls -al /usr/bin/perl
-rwxr-xr-x 2 root root 14836 Apr 3 2009 /usr/bin/perl
[root@ns7 ~]# chmod 700 /usr/bin/perl