Use utility file
, sample usage:
$ file /bin/bash
/bin/bash: Mach-O universal binary with 2 architectures
/bin/bash (for architecture x86_64): Mach-O 64-bit executable x86_64
/bin/bash (for architecture i386): Mach-O executable i386
$ file /etc/passwd
/etc/passwd: ASCII English text
$ file code.c
code.c: ASCII c program text
file
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