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I have a shell script in which I am running perl script by below code.

perl perlscript.pl

In the perl script I have defined a variable called $circle. Now I want to use this variable value in my shell script. How can I call?

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2  
Does your Perl script produce any other output to stdout? – roaima May 7 at 8:41
    
You can use perl code to update your PATH and set an environment variable. – Dac Saunders May 7 at 8:58
    
please provide more details. e.g. sample output from your perlscript.pl and maybe the script itself (or a minimal versison of it). – cas May 7 at 10:09
    
Put your perl scritp into your post. – PersianGulf May 7 at 13:43
    
@Programmer400, you cannot. You can alter the variables while the perl script is running but once it exits, whatever it changed will exit along with it. – glenn jackman May 8 at 1:06
up vote 4 down vote accepted

If your perl script produces no other output than the value of $circle, you can use command substitution to store that output in a variable. For example:

circle=$(perl perlscript.pl)

If the perl script produces other output as well (or not output at all), you'll have to either:

  1. extract only the value you want from the output using the usual text processing tools (sed, awk, perl, grep, etc). Here's a very simple example:

    circle=$(perl perlscript.pl | sed -e 's/junk.i.dont.want//')

  2. use an indirect method, such as having the perl script write the value of $circle to a file (e.g. /path/to/circle) for your shell to read it (e.g. circle=$(cat /path/to/circle))

NOTE: Without more details from you, it's impossible to provide more than generic advice like this.

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up vote -3 down vote

Just set an environment variable in perl and your shell will find it. In C you can check your path like this

void getPath() {
    if (getenv("PATH") == NULL) {
        printf("'%s' is not set.\n", "PATH");
        /* Default our path if it is not set. */
        putenv("PATH=/bin:/usr/bin:/sbin:/usr/sbin:/etc");
    }
    else if (getenv("PATH")) {
        printf("'%s' is set to %s.\n", "PATH", (getenv("PATH")));
    }
}

There are also functions for setting your path, so you can set an environment variable for your program in your code.

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2  
child processes (e.g. a perl script) can't change the parent's (e.g. the shell that the perl script was run from) environment. – cas May 7 at 9:36
    
@cas But you can have 2 shells at once can't I? – Dac Saunders May 7 at 9:54
3  
yes, but a child process still can't change its parent's environment. or the environment of an entirely unrelated process (e.g. a 2nd shell). it can affect the environment of itself and any child processes it creates. – cas May 7 at 9:59

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