CODEWITHSUNDEEP
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TTaJTa4
TTaJTa4

Reputation: 840

How to determine if the tcsh script is being sourced within the script [tcsh, not bash]

How can I determine if the current tcsh script is being sourced (within the script)?

What I tried:

if (!($0 == "-tcsh")) then
    echo "Script should be sourced."
    exit 1
endif

If I'll try without source it will print Script should be sourced. (As expected).

But If I'll try with source, it will fail with the following error: if: Malformed file inquiry..

How can I fix this problem? Is there a better way to check it?

Upvotes: 0

Views: 1006

Answers (3)

J2N
J2N

Reputation: 1

kvantour's anwser is wrong. In tcsh the value of $_ will not be set correctly unless the script is sourced from a command line/terminal. There is a guy at Intel that works on their icc compiler that must think the same way, which is where my issue is.

Simple example to prove the point:

script.csh:

#!/bin/csh
echo "Got: " $_

In a terminal:

Run source script.csh; you will get the output of "Got: source script.csh"

Run script.csh; you will get the output of "Got: "

Run ssh $HOST 'source script.csh'; you will get the output of "Got: "

So even though you sourced the script the $_ value is not set. This happens when you have a headless terminal. So if I put source scripts.csh inside of my .cshrc, $_ will not be set, which causes issues. So do not implement the solution here.

If I find the right answer I will update this post.

Upvotes: 0

kishore
kishore

Reputation: 86

While there might be other ways to do that, a simple enhancement to your own method works fine. Just enclose the $0 within double quotes. i.e change the line

if (!($0 == "-tcsh")) then

to

if (!("$0" == "-tcsh")) then

Upvotes: 0

kvantour
kvantour

Reputation: 26471

There is a nasty trick you can play here by looking at $_.

$_ Substitutes the command line of the last command executed.

If you place this in the first line of your script, and the outcome is not an empty string (i.e. a command has been executed before), then the script has been sourced.

#!/usr/bin/env tcsh
set sourced = ($_)
if ("$sourced" == "") then
   echo "Script should be sourced."
   exit 1
endif

Information picked from https://unix.stackexchange.com/questions/4650/determining-path-to-sourced-shell-script

Upvotes: 2

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