linux shuf 随机选择器

# shuf --help
Usage: shuf [OPTION]... [FILE]
or:  shuf -e [OPTION]... [ARG]...
or:  shuf -i LO-HI [OPTION]...
Write a random permutation of the input lines to standard output.

Mandatory arguments to long options are mandatory for short options too.
-e, --echo                treat each ARG as an input line
-i, --input-range=LO-HI   treat each number LO through HI as an input line
-n, --head-count=COUNT    output at most COUNT lines
-o, --output=FILE         write result to FILE instead of standard output
--random-source=FILE  get random bytes from FILE
-r, --repeat              output lines can be repeated
-z, --zero-terminated     end lines with 0 byte, not newline
--help     display this help and exit
--version  output version information and exit

With no FILE, or when FILE is -, read standard input.

GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
For complete documentation, run: info coreutils 'shuf invocation'