find ./ -name "my-elasticsearch.log" | xargs grep --color=auto "elasticsearch"

tail -100f log_file.log

grep -rn "二狗子" /logs/web.log --color

grep -rn '' web.log --color -C 

zcat /logs/log.--.log.gz | grep '' --color

zgrep --color '' /logs/log.--.log.gz

# 同时满足多条件

zcat /logs/log.--.log.gz | grep 'A' | grep 'B' --color

zgrep 'A' /logs/log.--.log.gz | grep 'B' --color

# 满足任一条件

zcat /logs/log.--.log.gz | grep -E 'A|B|C' --color

zgrep --color -E 'A|B|C' /logs/log.--.log.gz

# 目标地址是ip

$ telnet -b [本机地址] [目标地址] 

# 目标地址是url，不要带http://

$ telnet -b [本机地址] xxx.api.com

Trying xxx.xx.xx.xxx...

Connected to xxx.api.com.

Escape character is '^]'.

grep 'key' app.log | wc -l

================grep================

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.c

Regexp 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  byte, not newline

Miscellaneous:

  -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                ignored for backwards compatibility

Output 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 filename for each match

  -h, --no-filename         suppress the prefixing filename on output

      --label=LABEL         print LABEL as filename for standard input

  -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, -r, --recursive       equivalent to --directories=recurse

      --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  byte after FILE name

Context 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)

  -u, --unix-byte-offsets   report offsets as if CRs were not there (MSDOS)

`egrep' means `grep -E'.  `fgrep' means `grep -F'.

Direct invocation as either `egrep' or `fgrep' is deprecated.

With no FILE, or when FILE is -, read standard input.  If less than two FILEs

are given, assume -h.  Exit status is  if any line was selected,  otherwise;

if any error occurs and -q was not given, the exit status is .

================zgrep================

Usage: /usr/bin/zgrep [OPTION]... [-e] PATTERN [FILE]...

Look for instances of PATTERN in the input FILEs, using their

uncompressed contents if they are compressed.

OPTIONs are the same as for 'grep'.