While I'm reading file(1) I noticed this in the man page (emphasis mine):
When adding local definitions to /etc/magic, make sure to preserve these keywords. Users depend on knowing that all the readable files in a directory have the word “text” printed. Don't do as Berkeley did and change “shell commands text” to “shell script”.
What's the story behind this sentence? I guess Berkeley refers to BSD (Berkeley software distribution) but Google didn't give enough information about this.
Link to file(1) http://man7.org/linux/man-pages/man1/file.1.html
Some digging around shows that this statement was added 27 years ago link
Don't do as one computer vendor did \- change ``shell commands text'' to ``shell script''. and later changed to current statement link
Don't do as Berkeley did \- change ``shell commands text'' 
