介绍
在Linux系统中这统计非常方便，只需要简单的几个命令就可以搞定，这个命令就是 wc。
wc --help
用法：wc [选项]... [文件]...或：wc [选项]... --files0-from=F
输出每个指定文件的行数、单词计数和字节数，如果指定了
多于一个文件，继续给出所有相关数据的总计。如果没有指定
文件，或者文件为"-"，则从标准输入读取数据。-c, --bytes 输出字节数统计-m, --chars 输出字符数统计-l, --lines 输出行数统计--files0-from=文件 从指定文件读取以NUL 终止的名称，如果该文件被指定为"-"则从标准输入读文件名-L, --max-line-length 显示最长行的长度-w, --words 显示单词计数--help 显示此帮助信息并退出--version 显示版本信息并退出
使用实例
- 获取文件行数
wc -l app.log
30000 app.log
- 获取文件单词数
wc -w app.log
30000 app.log
- 获取文件字节数
wc -c app.log
3000 app.log
grep
查询文件的行数或字数只是个简单的需求场景，有时候我们其实是要获取多少匹配关键字的行数，那么这种情况如何实现呢，这种情况我们需要使用另外一个grep命令来配置wc来完成我们的需求场景。
lennlouis@dpdk-vm:~$ grep --help
Usage: grep [OPTION]... PATTERNS [FILE]...
Search for PATTERNS in each FILE.
Example: grep -i 'hello world' menu.h main.c
PATTERNS can contain multiple patterns separated by newlines.Pattern selection and interpretation:-E, --extended-regexp PATTERNS are extended regular expressions-F, --fixed-strings PATTERNS are strings-G, --basic-regexp PATTERNS are basic regular expressions-P, --perl-regexp PATTERNS are Perl regular expressions-e, --regexp=PATTERNS use PATTERNS for matching-f, --file=FILE take PATTERNS from FILE-i, --ignore-case ignore case distinctions in patterns and data--no-ignore-case do not ignore case distinctions (default)-w, --word-regexp match only whole words-x, --line-regexp match only whole lines-z, --null-data a data line ends in 0 byte, not newlineMiscellaneous:-s, --no-messages suppress error messages-v, --invert-match select non-matching lines-V, --version display version information and exit--help display this help text and exitOutput control:-m, --max-count=NUM stop after NUM selected lines-b, --byte-offset print the byte offset with output lines-n, --line-number print line number with output lines--line-buffered flush output on every line-H, --with-filename print file name with output lines-h, --no-filename suppress the file name prefix on output--label=LABEL use LABEL as the standard input file name prefix-o, --only-matching show only nonempty parts of lines that match-q, --quiet, --silent suppress all normal output--binary-files=TYPE assume that binary files are TYPE;TYPE is 'binary', 'text', or 'without-match'-a, --text equivalent to --binary-files=text-I equivalent to --binary-files=without-match-d, --directories=ACTION how to handle directories;ACTION is 'read', 'recurse', or 'skip'-D, --devices=ACTION how to handle devices, FIFOs and sockets;ACTION is 'read' or 'skip'-r, --recursive like --directories=recurse-R, --dereference-recursive likewise, but follow all symlinks--include=GLOB search only files that match GLOB (a file pattern)--exclude=GLOB skip files that match GLOB--exclude-from=FILE skip files that match any file pattern from FILE--exclude-dir=GLOB skip directories that match GLOB-L, --files-without-match print only names of FILEs with no selected lines-l, --files-with-matches print only names of FILEs with selected lines-c, --count print only a count of selected lines per FILE-T, --initial-tab make tabs line up (if needed)-Z, --null print 0 byte after FILE nameContext control:-B, --before-context=NUM print NUM lines of leading context-A, --after-context=NUM print NUM lines of trailing context-C, --context=NUM print NUM lines of output context-NUM same as --context=NUM--color[=WHEN],--colour[=WHEN] use markers to highlight the matching strings;WHEN is 'always', 'never', or 'auto'-U, --binary do not strip CR characters at EOL (MSDOS/Windows)When FILE is '-', read standard input. With no FILE, read '.' if
recursive, '-' otherwise. With fewer than two FILEs, assume -h.
Exit status is 0 if any line (or file if -L) is selected, 1 otherwise;
if any error occurs and -q is not given, the exit status is 2.Report bugs to: bug-grep@gnu.org
GNU grep home page: <http://www.gnu.org/software/grep/>
General help using GNU software: <https://www.gnu.org/gethelp/>- 查询文件中单词的行数
grep 'hello' app.log | wc -l
