Running unix commands in a perl script

Shell Programming and Scripting
1

Executing two unix commads via perl script one after another

e.g: make clean
bsub -i -q short make

have tried using exec but the second command doesnt executes

2 
$ perldoc -f exec

       exec LIST
       exec PROGRAM LIST
               The "exec" function executes a system command and never
               returns-- use "system" instead of "exec" if you want it to
               return.  It fails and returns false only if the command does
               not exist and it is executed directly instead of via your system's
               command shell (see below). 
      ...