Hi Monks, I'm currently modifying the Linux connection shell script for my University's network (to improve efficiency and connection success) and have found an interesting conundrum: bash works fine as a shell, sh doesn't (no known data for other shells yet).

So I've written a small perl program to pull the current shell out of env's output and warn the user if they're not running bash (code below): 

#!/usr/bin/perl -w
# shellGet.pl
# A program to return the current shell of the user
#
# Christopher Dykes (2008-09-30)

#Use the following modules:
use strict;    #Use strict syntax
use warnings;    #Enable warnings

#Get the environment data write it externally and open it for use:
system("env > .env.txt");
open(ENV, ".env.txt") || die("Couldn't open environment data file: $!"
+);

while(my $fileLine = <ENV>)                #Read in our environment fi
+le
{
    if($fileLine =~ /SHELL=/)            #Search for the shell line
    {
        my @shellLine = split(/=/, $fileLine);    #Extract the relevan
+t portion
        print "$shellLine[1]";            #Display our shell

        #All done:
        close ENV;                #Close the environment file
        system("rm .env.txt > /dev/null");    #Clean up the environmen
+t file
        exit;                    #And Quit
    }
}
#We shouldn't get here unless there's been an error:
die("\aError: Couldn't find SHELL\texiting\n");

[download]

This works, but it's more a question of efficiency is this the fastest way to do this (unlikely) and if there is a faster way can you give me any hints.

Thanks in advance Chris

In reply to Environment discovery under Linux by The Hindmost

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