Options to a command specified in a file

Question

How can I have some of the options to a unix command come from a file? That is the file does not contain all the options -- other options are specified elsewhere.

For example I have the filelsoptions.txt with the following content:

-F -G

Now I would like to execute

ls -a <and all options specified in the file lsoptons.txt>

ie, I want to execute ls -a -F -G.

That is, specify some of the options, but other options are read from a file.

Note:

• This is obviously a cooked up example. My real use case is that my shell script needs some parameters that were provided in a TeX file. So, instead of having the user duplicate the information in multiple places, I will have the TeX write the desired options into a file so that the shell script can also have access to them. One option would be to have the TeX generate the entire script, but would much easier if I could just read the options from a file.

Answer 1

For the trivial example listed above,

ls -a $(cat lsoptions.txt)