Recognize the format of any file using the file command!

The file command provides you useful information about any file.

For example, here is the output for a text file:

file license.txt
license.txt: ASCII English text, with CRLF line terminators

And here is one for a binary file. (The whoami util.)

file /usr/bin/whoami
/usr/bin/whoami: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.15, stripped

Lots of good information regarding the CPU architecture (Intel i386)

And here is the output using an image file:

file zenhub.png
zenhub.png: PNG image data, 900 x 699, 8-bit/color RGB, non-interlaced

file is truly a great utility and I can see myself using it quite a bit in the future. :)