How to create a custom magic file database

Question

The unix file command uses a \"magic\" file database to determine which type of data a file contains, independently of the file\'s name or extension.

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Answer 1

In this article: https://linux.die.net/man/1/file (or man file)

search for magic.mgc for explanation

The information identifying these files is read from the compiled magic file /usr/share/file/magic.mgc, or /usr/share/file/magic if the compile file does not exist. In addition file will look in $HOME/.magic.mgc, or $HOME/.magic for magic entries.