Last checked against version 3.39.
file tests each specified file in an attempt to classify it. There are three sets of tests, performed in this order: filesystem tests, magic number tests and language tests. The first test that succeeds causes the file type to be printed.
Last checked against version 3.37.
Autoconf: autoconf, autoheader
Automake: aclocal, automake
Bash: sh
Binutils: as, ld
Diffutils: cmp
Fileutils: chmod, install, ln, ls, mv, rm, touch
Gcc: cc1, collect2, cpp0, gcc
Grep: egrep, grep
M4: m4
Make: make
Gawk: gawk
Sed: sed
Sh-utils: echo, expr, hostname, sleep
Texinfo: makeinfo
Textutils: cat, tr