How to execute one command on all files within a folder

Question

Saying, I have this tree and I want to execute ruby on all scripts within the folder. How could I archive through one line of command.

./
../
rb-script/
    sample1.rb
    sample2.rb

Answer 1

Something along the lines (depending on your shell) of

for file in rb-script/*.rb; do ruby "$file"; done

should do the trick; alternatively (and shell-independently, I think)

find rb-script -type f -exec ruby "{}" \;

using find; where you can, depending on your situation, be more specific, à la

find rb-script -maxdepth 1 -type f -name '*.rb' -exec ruby "{}" \;

In general, command <glob-pattern> would also work if command accepts several files (and there are less files than the commandline argument maximum of your shell), but I doubt ruby does that. (You could write a wrapper script such that ruby-wrapper rb-script/*.rb would do what you want, though.)

Answer 2

If this will be part of a daemon, you could use the run-parts command to execute everything in the folder in alphabetical order. This command is especially useful if you need to execute it in reverse order for shutdown.