UNIX grep Command

HP-UX 에서 man 으로 확인한것이다.

요점만 색칠해서 보기 쉽게 하겠다.

자주사용 될만한 옵션만.(간단설명도 쓰겠습니다.)

$ man grep [☜ 엔터]

온라인 도움말을 다시 서식화합니다. 기다리십시오...

 NAME

      grep, egrep, fgrep - search a file for a pattern (패턴으로 검색하기)

 SYNOPSIS

    Plain call with pattern

      grep [-E|-F] [-c|-l|-q] [-bhinsvwx] pattern [file ...]

    Call with (multiple) -e pattern

      grep [-E|-F] [-c|-l|-q] [-bhinsvwx] -e pattern...  [-e pattern] ...

           [file ...]

    Call with -f file

      grep [-E|-F] [-c|-l|-q] [-bhinsvwx] [-f pattern_file] [file ...]

    Obsolescent:

      egrep [-cefilnsv] [expression] [file ...]

      fgrep [-cefilnsvx] [strings] [file ...]

 DESCRIPTION

      The grep command searches the input text files (standard input

      default) for lines matching a pattern.  Normally, each line found is

      copied to the standard output.  grep supports the Basic Regular

      Expression syntax (see regexp(5)).  The -E option (egrep) supports

      Extended Regular Expression (ERE) syntax (see regexp(5)).  The -F

      option (fgrep) searches for fixed strings using the fast Boyer-Moore

      string searching algorithm.  The -E and -F options treat newlines

      embedded in the pattern as alternation characters.  A null expression

      or string matches every line.

      The forms egrep and fgrep are maintained for backward compatibility.

      The use of the -E and -F options is recommended for portability.

    Options

           -E                  Extended regular expressions.  Each pattern

                               specified is a sequence of one or more EREs.

                               The EREs can be separated by newline

                               characters or given in separate -e expression

                               options.  A pattern matches an input line if

                               any ERE in the sequence matches the contents

                               of the input line without its trailing

                               newline character.  The same functionality is

                               obtained by using egrep.

           -F                  Fixed strings.  Each pattern specified is a

                               sequence of one or more strings.  Strings can

                               be separated by newline characters or given

                               in separate -e expression options.  A pattern

                               matches an input line if the line contains

                               any of the strings in the sequence.  The same

                               functionality is obtained by using fgrep.

           -b                  Each line is preceded by the block number on

                               which it was found.  This is useful in

                               locating disk block numbers by context.

                               Block numbers are calculated by dividing by

                               512 the number of bytes that have been read

                               from the file and rounding down the result.

           -c                  Only a count of matching lines is printed.(카운트 숫자표시)

           -e expression       Same as a simple expression argument, but

                               useful when the expression begins with a

                               hyphen (-).  Multiple -e options can be used

                               to specify multiple patterns; an input line

                               is selected if it matches any of the

                               specified patterns.

           -f pattern_file     The regular expression (grep and grep -E) or

                               strings list (grep -F) is taken from the

                               pattern_file.

           -h                  Suppress printing of filenames when searching

                               multiple files.

           -i                  Ignore uppercase/lowercase (대소문자 무시함) distinctions

                               during comparisons.

           -l                  Only the names of files with matching lines

                               are listed (once), separated by newlines.  If

                               standard input is searched, a path name of

                               (standard input) will be written, in the

                               POSIX locale. In other locales, (standard

                               input) may be replaced by something more

                               appropriate in those locales.

           -n                  Each line is preceded by its relative line

                               number (해당파일의 라인을 표시함) in the file starting at 1.  The line

                               number is reset for each file searched.  This

                               option is ignored if -c, -b, -l, or -q is

                               specified.

           -q                  (Quiet) Do not write anything to the standard

                               output, regardless of matching lines.  Exit

                               with zero status upon finding the first

                               matching line.  Overrides any options that

                               would produce output.

           -s                  Error messages produced for nonexistent or

                               unreadable files are suppressed.

           -v                  All lines but those matching are printed.

           -w                  Select only those lines containing matches

                               that form whole words.(전체단어일치) The test is that the

                               matching substring must either be at the

                               beginning of the line, or preceded by a non-

                               word constituent character.  Similarly, it

                               must be either at the end of the line or

                               followed by a non-word constituent character.

                               Word-constituent characters are letters,

                               digits, and the underscore.

           -x                  (eXact) Matches are recognized only when the

                               entire input line matches the fixed string or

                               regular expression.

      The file name is output in all the cases in which output is generated

      if there are more than one input file, unless the -h option is

      specified.  Care should be taken when using the characters $, *, [, ^,

      |, (, ), and \ in expression, because they are also meaningful to the

      shell.  It is safest to enclose the entire expression argument in

      single quotes ('...').

 EXTERNAL INFLUENCES

    Environment Variables

      LANG determines the locale to use for the locale categories when both

      LC_ALL and the corresponding environment variable (beginning with LC_)

      do not specify a locale.  If LANG is not specified or is set to the

      empty string, a default of C (see lang(5)) is used.

      LC_ALL determines the locale to use to override any values for locale

      categories specified by the settings of LANG or any environment

      variables beginning with LC_.

      LC_COLLATE determines the collating sequence used in evaluating

      regular expressions.

      LC_CTYPE determines the interpretation of text as single byte and/or

      multi-byte characters, the classification of characters as letters,

      the case information for the -i option, and the characters matched by

      character class expressions in regular expressions.

      LC_MESSAGES determines the language in which messages are displayed.

      If any internationalization variable contains an invalid setting, the

      commands behave as if all internationalization variables are set to C.

      See environ(5).

    International Code Set Support

      Single-byte and multi-byte character code sets are supported.

 RETURN VALUE

      Upon completion, grep returns one of the following values:

           0    One or more matches found.

           1    No match found.

           2    Syntax error or inaccessible file (even if matches were

                found).

 

EXAMPLES

      In the POSIX shell (sh(1)) the following example searches two files,

      finding all lines containing occurrences of any of four strings:

           grep -F 'if

           then

           else

           fi' file1 file2

      Note that the single quotes are necessary to tell grep -F when the

      strings have ended and the file names have begun.

      For the C shell (see csh(1)) the following command can be used:

           grep -F 'if\  then\  else\ fi'  file1  file2

      To search a file named address containing the following entries:

           Ken   112 Warring St.  Apt. A

           Judy  387 Bowditch  Apt. 12

           Ann   429 Sixth St.

      the command:

           grep Judy address

      prints:

           Judy  387 Bowditch  Apt. 12

      To search a file for lines that contain either a Dec or Nov, use

      either of the following commands:

           grep -E '[Dd]ec|[Nn]ov' file

           egrep -i 'dec|nov' file

      Search all files in the current directory for the string xyz:

           grep xyz *

      Search all files in the current directory subtree for the string xyz,

      and ensure that no error occurs due to file name expansion exceeding

      system argument list limits:

           find . -type f -print |xargs grep xyz

      The previous example does not print the name of files where string xyz

      appears.  To force grep to print file names, add a second argument to

      the grep command portion of the command line:

           find . -type f -print |xargs grep xyz /dev/null

      In this form, the first file name is that produced by find, and the

      second file name is the null file.

 WARNINGS

      (XPG4 only.) If the -q option is specified, the exit status will be

      zero if an input line is selected, even if an error was detected.

      Otherwise, default actions will be performed.

      If the -w option is specified with non-word constituent characters,

      then the output is unexpected.

 SEE ALSO

      sed(1), sh(1), regcomp(3C), environ(5), lang(5), regexp(5).

 STANDARDS CONFORMANCE

      grep: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2

      egrep: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2

      fgrep: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2