linux中grep是一个常用的命令,我们执行grep –help可以看到他的用法还有实例如下:Usage: grep [OPTION]… PATTERN [FILE]…Search for PATTERN in each FILE or standard input.PATTERN is, by default, a basic regular expression (BRE).Example: grep -i ‘hello world’ menu.h main.cRegexp selection and interpretation: -E, –extended-regexp PATTERN is an extended regular expression (ERE) -F, –fixed-strings PATTERN is a set of newline-separated fixed strings -G, –basic-regexp PATTERN is a basic regular expression (BRE) -P, –perl-regexp PATTERN is a Perl regular expression -e, –regexp=PATTERN use PATTERN for matching -f, –file=FILE obtain PATTERN from FILE -i, –ignore-case ignore case distinctions -w, –word-regexp force PATTERN to match only whole words -x, –line-regexp force PATTERN to 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 print version information and exit –help display this help and exit –mmap deprecated no-op; evokes a warningOutput control: -m, –max-count=NUM stop after NUM matches -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 the file name for each match -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 the part of a line matching PATTERN -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=FILE_PATTERN search only files that match FILE_PATTERN –exclude=FILE_PATTERN skip files and directories matching FILE_PATTERN –exclude-from=FILE skip files matching any file pattern from FILE –exclude-dir=PATTERN directories that match PATTERN will be skipped. -L, –files-without-match print only names of FILEs containing no match -l, –files-with-matches print only names of FILEs containing matches -c, –count print only a count of matching 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) -u, –unix-byte-offsets report offsets as if CRs were not there (MSDOS/Windows)’egrep’ means ‘grep -E’. ‘fgrep’ means ‘grep -F’.Direct invocation as either ‘egrep’ or ‘fgrep’ is deprecated.When FILE is -, read standard input. With no FILE, read . if a command-line-r is given, – otherwise. If fewer than two FILEs are given, assume -h.Exit status is 0 if any line is selected, 1 otherwise;if any error occurs and -q is not given, the exit status is 2.
