Shell Programming and Scripting

#Script Starts here 
#!/usr/local/bin/perl
#Program to find the disk space and to delete the older files
#Checks the type of OS here
$OS = `uname -a | awk '{print $1}'`;
print ("The Operating System is $OS");
if ($OS == SunOS ) {
   
    print ("Enter the filesystem related to SUN \n");
    $FILESYSTEM = <STDIN>;
     
    $DF = `df -sk $FILESYSTEM | awk '{print $3,$4,$5}' | awk '{if($3>50)print $3}'`;
    
    print ("The file system $ FILESYSTEM usage is $DF \n");
    while ($DF > 50){
    
    print ("The file system $FILESYSTEM reached its maximum capacity $DF and request you to clear the space /n");
    print ("Please enter "YES" if you want to delete the files which is consuming more space /n");
    print ("Please enter "NO" if you want to proceed as it is /n");
 
    $OPTION = <STDIN>;
    given ($OPTION) {
    when ("YES")  { `find $FILESYSTEM -size +5242880c -size -10485760c 2>/dev/null -print | xargs -i rm -i {}` }
                  { Print "The file system which is consuming more space has been removed \n" }
                  break;
    when ("NO") { exit (); }
 
    }
    }
    } elsif ($OS == HP-UX) {
    print ("Please enter the filesystem related to HP-UX \n");
    $FILESYSTEM1 = <STDIN>;
    $DF1 = `bdf $FILESYSTEM1 | awk -F " " '{ print $3,$4,$5 }' | xargs -i cut -f 3 -d " " {}`;
    print ("The file system $ FILESYSTEM usage is $DF \n");
    
    while ($DF1 > 50){
    print ("The file system $FILESYSTEM1 usage is $DF1 and request you to clear the space \n");
    }
#End Of Script
    }

`find $FILESYSTEM -xdev -type f \( -size +5242880c -a -size -10485760c \) -print 2>/dev/null | xargs -i echo rm -i {}``

DF1 = `bdf $FILESYSTEM1 | grep -v "Filesystem"|sed -e "s/%//g"|awk '{print $5}'`

df -h $FILESYSTEM -exec | grep -v "Filesystem" | sed -e "s/%//g"|awk '{print $5}'

bash-2.05$ ./diskusage.pl
The Operating System is SunOS
Enter the filesystem related to SUN
/u001
sh: syntax error at line 2: `|' unexpected