Cleanest and safest way to invoke long commands including pipes and/or chains

[sla-te]

e.g.

cd var/backup/files && tar cf `date "+%Y-%m-%d"`_files.tar /some_path/news/  /some_path/media/  && ls -tp | grep -v "/$" | tail -n +21 | xargs -I {} rm -- {}

I would now start to use shlex.split on it, iterate and do poor mans comparissions like:

import shlex
cur_cmd: list[str] = []
for item in shlex.split(long_cmd):
    if item in ("&&", ";"):
        assemble_sh_cmd(cur_cmd)
        cur_cmd = [item]
        continue
    elif item in ("|", "||"):
        assemble_sh_cmd(cur_cmd, is_pipe=True)
        cur_cmd = [item]
        continue

    cur_cmd.append(item)

Is there not a much better way to handle such cases?

[amoffat]

The short answer is no. Acting like a full shell is outside of the scope of the project, even though it does include some shell utilities. Sh is primarily for command execution.

I would convert the trivial parts to Python and execute the non-trivial parts with sh. The example that you gave is all trivial, as Python can list directories, do regex comparisons, remove files, and tar files. If parts of the command called binaries that are not portable to Python, that's where you would use sh.

[sla-te]

Thanks for the quick response, I was already assuming it could be this way - cleaner anyway so I will rewrite it accordingly.