On Fri, 29 Oct 2004, Durai raj wrote: > Anyone can explain the difference between Perl and Shell scripts?
They're completely separate languages. On Unix systems, a "shell" is a program that receives input and sends results down to the kernel to be executed, thus the name "shell" -- it's an easier way to work than trying to talk to the kernel directly. Common shells include bash, ksh, zsh, tcsh, csh, and sh. The last one is called the Bourne shell; it is the original and most others resemble it. A series of shell statements that could otherwise be run directly at the command line prompt can also be saved as a shell script and run that way, much like a DOS batch script. These scripts are typically written in the Bourne shell (sh), because that's the one most likely to be installed on any given Unix system, but shell scripts can be written in any shell language. People will look at you funny if you write them using the csh shell, but even that one can be used :-) On the other hand, Perl is a programming language that was designed with ideas from many places, including the different Unix shells, languages like C, Basic & Lisp, and Unix system commands like Sed and Awk. A lot of Perl's core functions look and act like well known shell commands -- grep, chmod, etc -- but this is only to help make Perl easy to learn for someone already familiar with those commands. Perl is separate from the Unix shells. You can have some overlap -- a shell script can make use of all sorts of programs, including perl, and a Perl script can run shell commands with system( ... ) or `...` -- but in general, well written shell scripts don't need Perl and well written Perl scripts don't need external shell commands. Clearer? -- Chris Devers [EMAIL PROTECTED] http://devers.homeip.net:8080/blog/ -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] <http://learn.perl.org/> <http://learn.perl.org/first-response>
