Porting "Inplace Upgrading Of Llamafiles Engine Bash Script" to llamafile for general usage

[mofosyne]

Written a bash script in https://briankhuu.com/blog/2024/04/06/inplace-upgrading-of-llamafiles-engine-bash-script/ to help upgrade in place older llamafiles with newer llamafile engines. We may want to port and adapt this into something more robust for common usage in llamafile repo.

Impulse for this issue

jart made a quick tutorial in #24 to do something similar. Alerted about this script, she suggested to add it to llamafile repo. Suggested to place into build directory. Suggest to use llamafile-convert as inspiration on coding style and approach. (Preference to be compatible with almquist (posix) shell).

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Status:

• PR Added Script To Upgrade llamafile Archives #412 created. Requesting review
• Thinking of naming the script llamafile-upgrade-engine