How to expand shell variables in a text file?

Question

Consider a ASCII text file (lets say it contains code of a non-shell scripting language):

Text_File.msh:

spool on to \'$LOG_FILE_PATH/lo         


        

Answer 1

If a Perl solution is ok for you:

Sample file:

$ cat file.sh
spool on to '$HOME/logfile.log';
login 'username' 'password';

Solution:

$ perl -pe 's/\$(\w+)/$ENV{$1}/g' file.sh
spool on to '/home/user/logfile.log';
login 'username' 'password';