简介
wc 命令可以帮助我们计算文件的字节数、字数、或者文件的行数，常用于统计文件的相关信息。
wc 命令的 帮助信息比较简短：
[root@A23488811 test]# wc --help
Usage: wc [OPTION]... [FILE]...
or: wc [OPTION]... --files0-from=F
Print newline, word, and byte counts for each FILE, and a total line if
more than one FILE is specified. With no FILE, or when FILE is -,
read standard input. A word is a non-zero-length sequence of characters
delimited by white space.
The options below may be used to select which counts are printed, always in
the following order: newline, word, character, byte, maximum line length.
-c, --bytes print the byte counts
-m, --chars print the character counts
-l, --lines print the newline counts
--files0-from=F read input from the files specified by
NUL-terminated names in file F;
If F is - then read names from standard input
-L, --max-line-length print the length of the longest line
-w, --words print the word counts
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
For complete documentation, run: info coreutils 'wc invocation'
参数选项
支持的主要参数选项包括：
-
-c：统计字节数 -
-m：统计字符数，该参数不能与-c一起使用 -
-l：统计行数 -
-w：统计字数，这里的字指的是由空格、换行符等分隔的字符串
示例
使用以下的文件作为测试文件：
[root@A23488811 test]# cat testfile
Linux networks are becoming more and more common, but scurity is often an overlooked
issue. Unfortunately, in today’s environment all networks are potential hacker targets,
fro0m tp-secret military research networks to small home LANs.
Linux Network Securty focuses on securing Linux in a networked environment, where the
security of the entire network needs to be considered rather than just isolated machines.
It uses a mix of theory and practicl techniques to teach administrators how to install and
use security applications, as well as how the applcations work and why they are necesary.
[root@A23488811 test]#
对测试文件直接使用 wc 命令：
[root@A23488811 test]# wc testfile
7 92 608 testfile
7 表示测试文件的行数，92 表示测试文件的字数，608 表示测试文件的字节数：
[root@A23488811 test]# wc -l testfile
7 testfile
[root@A23488811 test]# wc -w testfile
92 testfile
[root@A23488811 test]# wc -c testfile
608 testfile
可以通过命令输出的重定向功能，使得 wc 命令获得更广泛的使用方式，比如
[root@A23488811 test]# ll
total 16
drwxr-xr-x 2 root root 6 May 31 09:37 test
-rw-r--r-- 1 root root 608 May 31 09:29 testfile
-rw-r--r-- 1 root root 608 May 31 09:37 testfile1
-rw-r--r-- 1 root root 608 May 31 09:37 testfile2
-rw-r--r-- 1 root root 608 May 31 09:37 testfile3
[root@A23488811 test]#
[root@A23488811 test]#
[root@A23488811 test]# ll | grep "^-" | wc -l
4
以上命令可以统计当前目录下具有多少个普通文件。其中 grep "^-" 表示获取以 - 开头的行，这些行表示的都是普通文件，通过命令输出的重定向，作为 wc 命令的输入，可统计出当前目录下普通文件的数量。
