File (command)

file is a command to find out the type of a given file. Because for Linux, "everything is a file", it can distinguish a lot:

• hard disks

# file /dev/sda1
/dev/sda1: block special (8/1)

• file systems

# file -s /dev/sdc
/dev/sdc: Linux rev 1.0 ext3 filesystem data (needs journal recovery) (large files)

• directories

# file /tmp
/tmp: sticky directory

• links

# file /lib64/libkeyutils.so.1
/lib64/libkeyutils.so.1: symbolic link to `libkeyutils-1.2.so'

• normal files

# file /lib64/libkeyutils-1.2.so
/lib64/libkeyutils-1.2.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), stripped