For djvused command, there is an option:
Cause djvused to execute the commands specified by the option argument commands. It is advisable to surround the djvused commands by single quotes in order to prevent unwanted shell expansion.
djvused myfile.djvu -e 'print-pure-txt'.
It is quite unusual to me in that a command (here djvused) can run other commands (here by
-e option). I was wondering how it is possible? Is this a frequent practice in command line interface?
Is this similar to print command used in awk command?
The only way I know for a command to be used in another command is:
echo `echo hello`
Thanks and regards!