A menu that would "add" the file or folder in a custom made (by the user) command string.
And, of course, that string would be then executed.
It could be something like this...
The right mouse click menu on a folder (or a file) would have an extra "Pipe to" item,
pointing to user defined "subitems"...
Pipe to... ------> Smplayer
-------------- Flac to Mp3
The user might have added the following strings, in his "xferc"...
( the '%s' symbol would reffer to the selected file or directory
(full path, might have spaces),
and the "Name" would define how the string would show on the menu)
"Smplayer" smplayer '%s'
"Flac to Mp3" /home/nikos/apps/flac2mp3/flac2mp3.pl '%s' /home/nikos/tmp
"Baobab" baobab '%s'
"ffplay" xterm -e ffplay '%s'
smplayer -> play the file (or the folder'r conntent) with this particular media player
flac to mp3 -> convert the .flac files of this folder in .mp3
with the use of the flca2mp3 shell, and place the mp3 files
in /home/nikos/tmp directory
baobab -> open the folder with Baobab, a graphical tool to analyze disk usage.
ffplay -> open xterm, and then execute: ffplay 'file'
And to keep it simple, these submenu items would be file and folder wide.
The user made them, so he should know if they work for files or folders, or both.