Usage:

file file ...

The command file can be used to determine the file type and its character encoding.

• Display file type:
  

  $ echo "Hello ..." > file1
  $ ln -s file1 sfile1
  $ ln file1 hfile1
  $ echo "" > file2
  $ touch file3
  $ echo '#!/bin/bash' > script1.sh; chmod 755 script1.sh
  $ mkdir folder1

  
  

  $ ls -l ./
  -rw-rw-r-- 2   10  file1
  -rw-rw-r-- 1    1  file2
  -rw-rw-r-- 1    0  file3
  drwxrwxr-x 2 4096  folder1
  -rw-rw-r-- 2   10  hfile1
  -rwxr-xr-x 1   12  script1.sh
  lrwxrwxrwx 1    5  sfile1 -> file1

  
  

  $ file ./*
  ./file1:   ASCII text
  ./file2:   very short file (no magic)
  ./file3:   empty
  ./folder1: directory
  ./hfile1:  ASCII text
  ./script1.sh: Bourne-Again shell script, ASCII text executable
  ./sfile1:  symbolic link to file1

  
  You can use the option -i to display mime type and encoding of the file:
  

  $ file -i ./*
  ./file1:      text/plain; charset=us-ascii
  ./file2:      application/octet-stream; charset=binary
  ./file3:      inode/x-empty; charset=binary
  ./folder1:    inode/directory; charset=binary
  ./hfile1:     text/plain; charset=us-ascii
  ./script1.sh: text/x-shellscript; charset=us-ascii
  ./sfile1:     inode/symlink; charset=binary

  
  You can also use the command file to display the file type of an executable binary file (display the OS information and the libraries the executable requires):
  

  $ file -i /usr/lib/jvm/java-11-openjdk-amd64/bin/java
  /usr/lib/jvm/java-11-openjdk-amd64/bin/java: application/x-sharedlib; charset=binary

  
  

  $ file /usr/lib/jvm/java-11-openjdk-amd64/bin/java
  /usr/lib/jvm/java-11-openjdk-amd64/bin/java: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=0bae0045bc544e2d1ef0c59e0d7951e880e7aacd, stripped

The following options can be used:

    --help                 display this help and exit
-v, --version              output version information and exit
-m, --magic-file LIST      use LIST as a colon-separated list of magic number files
-z, --uncompress           try to look inside compressed files
-Z, --uncompress-noreport  only print the contents of compressed files
-b, --brief                do not prepend filenames to output lines
-c, --checking-printout    print the parsed form of the magic file, use in conjunction with -m to debug a new magic file before installing it
-e, --exclude TEST         exclude TEST from the list of test to be performed for file.
                           Valid tests are: apptype, ascii, cdf, compress, elf, encoding, soft, tar, text, tokens
-f, --files-from FILE      read the filenames to be examined from FILE
-F, --separator STRING     use string as separator instead of `:'
-i, --mime                 output MIME type strings (--mime-type and --mime-encoding)
    --apple                output the Apple CREATOR/TYPE
    --extension            output a slash-separated list of extensions
    --mime-type            output the MIME type
    --mime-encoding        output the MIME encoding
-k, --keep-going           don't stop at the first match
-l, --list                 list magic strength
-L, --dereference          follow symlinks (default if POSIXLY_CORRECT is set)
-h, --no-dereference       don't follow symlinks (default if POSIXLY_CORRECT is not set) (default)
-n, --no-buffer            do not buffer output
-N, --no-pad               do not pad output
-0, --print0               terminate filenames with ASCII NUL
-p, --preserve-date        preserve access times on files
-P, --parameter            set file engine parameter limits
                             indir        15 recursion limit for indirection
                             name         30 use limit for name/use magic
                             elf_notes   256 max ELF notes processed
                             elf_phnum   128 max ELF prog sections processed
                             elf_shnum 32768 max ELF sections processed
-r, --raw                  don't translate unprintable chars to \ooo
-s, --special-files        treat special (block/char devices) files as ordinary ones
-C, --compile              compile file specified by -m
-d, --debug                print debugging messages