"source" command inside a CSH scrip

Question

I wrote CSH script, include the following line:

bash -c 'source $file; exec csh'

When running, I get the next error:

bash: line 0: source: filename argument required source: usage: source

filename [arguments]

Thanks too much!

Answer 1

Lookup the difference between single quotes (') and double quotes (").

Since you are using single quotes, the variable is not expanded. I assume $file is a variable in the program where you are doing this.

Bash sees source $file; exec csh literally. It expands $file, but since that is not a variable to Bash, it expands to nothing. So the source command complains.

This works for me:

% set file='/tmp/bash_prog'
% bash -c "source $file; exec csh"
Hello from Bash!
%

Note how the last % is the prompt from the nested csh.