Going thru this thread checking if links are still good and info up to date. I have not seen a command mentioned I often find useful.

file <filename>

Will tell you the type of file it is.

poppageek@8356x2deb:~/BOINC$ file boinc
boinc: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.24, BuildID[sha1]=0x715e83716479c4a94b31cb45948d3e7ce245c02a, stripped
poppageek@8356x2deb:~/BOINC$ file binstall.sh
binstall.sh: ASCII text
poppageek@8356x2deb:~/BOINC$ file ca-bundle.crt
ca-bundle.crt: ASCII English text