file判断文件类型

[root@localhost bin]# file --help
Usage: file [OPTION...] [FILE...]
Determine type of FILEs.

      --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
  -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:
                               ascii, apptype, compress, elf, soft, tar, tokens, troff
  -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
      --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)
  -h, --no-dereference       don't follow symlinks
  -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
  -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

--文件夹
[root@localhost software]# file nginx-1.9.3
nginx-1.9.3: directory
--压缩包
[root@localhost software]# file jdk-7u79-linux-x64.gz
jdk-7u79-linux-x64.gz: gzip compressed data, from Unix, last modified: Fri Apr 10 11:53:41 2015
--DOS的bat文件
[root@localhost bin]# file startup.bat
startup.bat: DOS batch file, ASCII text, with CRLF line terminators
--Sheel脚本
[root@localhost bin]# file startup.sh
startup.sh: POSIX shell script, ASCII text executable