Chain to trim off first 25 seconds

I have spent days trying to figure out how to create a simple chain to cut off 25 seconds of the start of an mp3 file.
In the “Select Command” I see no effect choice of edit or trim, and I see no means to add those effects to the “Select Command” drop down menu!
It would be great to add or remove commands from “Select Command” drop down! Then it would be nice to run the chain through a directory of files!

It is not currently possible to do that in an Audacity Chain.

If you are comfortable with command line programs and batch files it can be done using SoX

It would be possible in Audacity if Audacity Chains supported Nyquist Plug-ins. This has been written and tested but has not yet been included in any release version of Audacity. If you would like to vote for adding this feature (Nyquist support in Chains) then let me know and I’ll move this post to the “Adding features” section of the forum.

I would think that timming time off of beginning and endings of music files would be a commonplace macro (chain)!
I would think that adding/deleting applicable effects to/from “select commands” dropdown menu would be commonplace setup!
I would like them to be considered in future improvements! Thanks

Perhaps surprisingly it does not seem to be very common. The question of trimming a set amount of time of the beginning/end of a file has come up before, but not very often.

Unfortunately it is not simple to do. The way that the code is currently written the effects that are available as Chain commands are hard coded so effects that are not bundled as standard in Audacity cannot be added without recompiling the source code. The changes proposed in the “Nyquist support in Chains” feature request makes an important change to how the Chain commands are called in that the Chain effect list is created at run-time from the list of currently installed effects. This change is (IMHO) a powerful addition to Chains as it would allow custom effects to be used for batch processing.

There is currently a proposal for this feature here:
I’ll add an example “user case” linking to this forum topic.