, , ,

Unix – Grep, egrep and Recursive Grep


# files containing "import" in subdirectories
grep -rHn  "import"  *

# files containing "import" or "except"
grep -rHnE "import|except" *

# only .py files containing "import" or "except"
grep --color --include="*.py" -rHnE "import|except" *

# python files, text files and java files
grep --color --include="*[py|txt|java]" -rHnE "^import [a-z,\s]+$" *

# same as above with extended
find . -regextype posix-extended -iregex ".*.py|.*.txt|.*.txt" -exec grep  --color -rHnE "import|except" '{}' \; -print
#find . -name "*.py" -exec grep  --color -rHnE "import|except" '{}' \; -print

# print file names only
find . -regextype posix-extended -iregex ".*.py|.*.txt|.*.java" -exec grep -rli "kch#opts=c#zcomp=lzo#c=true" '{}' \;


# egrep <==> grep with -e or -E
egrep -rHn 'recursive|fun|also' *

r = recursive
H = Print File names
n = Print Line Number
E = extended regex
–include=only match files with this regex name

grep -rHnE <==> egrep -rHn

1. print file name only

grep -rlin  "recursive" *

grep -rHEn "recursive|fun|also" *
egrep -rlin "recursive|fun|also"

2. regex with grep – print only filenames

grep -rHn "^import*" *

grep -le "import" *

#geek nr. 1 - find "import os" in "*.py" files
find . -name "*.py"  -exec grep -Hn "import os" '{}' \;

#geek nr. 2 - find "import os" in "*.py" files - same result as above
find . -name "*.py" |xargs grep -Hn "import os"

4. regex with grep

grep -e -H ""

search recursively for files and occurrences of the keyword “recursive”

5. grep man


GREP(1)                                      GREP(1)



NAME
       grep, egrep, fgrep, rgrep - print lines matching a pattern

SYNOPSIS
       grep [OPTIONS] PATTERN [FILE...]
       grep [OPTIONS] [-e PATTERN | -f FILE] [FILE...]

DESCRIPTION
       grep  searches  the  named  input  FILEs (or standard input if no files are named, or if a single hyphen-minus (-) is
       given as file name) for lines containing a match to the given PATTERN.  By default, grep prints the matching lines.

       In addition, three variant programs egrep, fgrep and rgrep are available.  egrep is the same as  grep -E.   fgrep  is
       the same as grep -F.  rgrep is the same as grep -r.  Direct invocation as either egrep or fgrep is deprecated, but is
       provided to allow historical applications that rely on them to run unmodified.

OPTIONS
   Generic Program Information
       --help Print a usage message briefly summarizing these command-line options and the bug-reporting address, then exit.

       -V, --version
              Print the version number of grep to the standard output stream.  This version number should be included in all
              bug reports (see below).

   Matcher Selection
       -E, --extended-regexp
              Interpret PATTERN as an extended regular expression (ERE, see below).  (-E is specified by POSIX.)

       -F, --fixed-strings
              Interpret  PATTERN  as  a list of fixed strings, separated by newlines, any of which is to be matched.  (-F is
              specified by POSIX.)

       -G, --basic-regexp
              Interpret PATTERN as a basic regular expression (BRE, see below).  This is the default.

       -P, --perl-regexp
              Interpret PATTERN as a Perl regular expression (PCRE, see below).  This is highly experimental and grep -P may
              warn of unimplemented features.

   Matching Control
       -e PATTERN, --regexp=PATTERN
              Use  PATTERN  as  the  pattern.  This can be used to specify multiple search patterns, or to protect a pattern
              beginning with a hyphen (-).  (-e is specified by POSIX.)

       -f FILE, --file=FILE
              Obtain patterns from FILE, one per line.  The  empty  file  contains  zero  patterns,  and  therefore  matches
              nothing.  (-f is specified by POSIX.)

       -i, --ignore-case
              Ignore case distinctions in both the PATTERN and the input files.  (-i is specified by POSIX.)

       -v, --invert-match
              Invert the sense of matching, to select non-matching lines.  (-v is specified by POSIX.)

       -w, --word-regexp
              Select  only  those  lines  containing matches that form whole words.  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, --line-regexp
              Select only those matches that exactly match the whole line.  (-x is specified by POSIX.)

       -y     Obsolete synonym for -i.

   General Output Control
       -c, --count
              Suppress normal output; instead print  a  count  of  matching  lines  for  each  input  file.   With  the  -v,
              --invert-match option (see below), count non-matching lines.  (-c is specified by POSIX.)

       --color[=WHEN], --colour[=WHEN]
              Surround  the  matched  (non-empty)  strings,  matching  lines,  context lines, file names, line numbers, byte
              offsets, and separators (for fields and groups of context lines) with escape  sequences  to  display  them  in
              color  on  the  terminal.   The  colors  are  defined by the environment variable GREP_COLORS.  The deprecated
              environment variable GREP_COLOR is still supported, but its setting does not have priority.   WHEN  is  never,
              always, or auto.

       -L, --files-without-match
              Suppress  normal  output;  instead  print the name of each input file from which no output would normally have
              been printed.  The scanning will stop on the first match.

       -l, --files-with-matches
              Suppress normal output; instead print the name of each input file from which output would normally  have  been
              printed.  The scanning will stop on the first match.  (-l is specified by POSIX.)

       -m NUM, --max-count=NUM
              Stop  reading  a  file  after NUM matching lines.  If the input is standard input from a regular file, and NUM
              matching lines are output, grep ensures that the standard input is positioned to just after the last  matching
              line  before exiting, regardless of the presence of trailing context lines.  This enables a calling process to
              resume a search.  When grep stops after NUM matching lines, it outputs any trailing context lines.   When  the
              -c  or  --count  option  is  also  used,  grep  does  not  output  a  count  greater than NUM.  When the -v or
              --invert-match option is also used, grep stops after outputting NUM non-matching lines.

       -o, --only-matching
              Print only the matched (non-empty) parts of a matching line, with each such part on a separate output line.

       -q, --quiet, --silent
              Quiet; do not write anything to standard output.  Exit immediately with zero status if  any  match  is  found,
              even if an error was detected.  Also see the -s or --no-messages option.  (-q is specified by POSIX.)

       -s, --no-messages
              Suppress error messages about nonexistent or unreadable files.  Portability note: unlike GNU grep, 7th Edition
              Unix grep did not conform to POSIX, because it lacked -q and its -s option behaved like GNU grep's -q  option.
              USG-style  grep  also  lacked -q but its -s option behaved like GNU grep.  Portable shell scripts should avoid
              both -q and -s and should redirect standard and error output  to  /dev/null  instead.   (-s  is  specified  by
              POSIX.)

   Output Line Prefix Control
       -b, --byte-offset
              Print  the  0-based  byte offset within the input file before each line of output.  If -o (--only-matching) is
              specified, print the offset of the matching part itself.

       -H, --with-filename
              Print the file name for each match.  This is the default when there is more than one file to search.

       -h, --no-filename
              Suppress the prefixing of file names on output.  This is the default when there is  only  one  file  (or  only
              standard input) to search.

       --label=LABEL
              Display  input actually coming from standard input as input coming from file LABEL.  This is especially useful
              when implementing tools like zgrep, e.g., gzip -cd foo.gz | grep --label=foo -H something.  See  also  the  -H
              option.

       -n, --line-number
              Prefix each line of output with the 1-based line number within its input file.  (-n is specified by POSIX.)

       -T, --initial-tab
              Make  sure  that  the first character of actual line content lies on a tab stop, so that the alignment of tabs
              looks normal.  This is useful with options that prefix their output to the actual content: -H,-n, and -b.   In
              order  to  improve  the probability that lines from a single file will all start at the same column, this also
              causes the line number and byte offset (if present) to be printed in a minimum size field width.

       -u, --unix-byte-offsets
              Report Unix-style byte offsets.  This switch causes grep to report byte offsets as if the file  were  a  Unix-
              style  text  file, i.e., with CR characters stripped off.  This will produce results identical to running grep
              on a Unix machine.  This option has no effect unless -b option is also used; it has  no  effect  on  platforms
              other than MS-DOS and MS-Windows.

       -Z, --null
              Output  a zero byte (the ASCII NUL character) instead of the character that normally follows a file name.  For
              example, grep -lZ outputs a zero byte after each file name instead of the usual newline.   This  option  makes
              the  output unambiguous, even in the presence of file names containing unusual characters like newlines.  This
              option can be used with commands like find -print0, perl -0, sort -z, and xargs -0 to process  arbitrary  file
              names, even those that contain newline characters.

   Context Line Control
       -A NUM, --after-context=NUM
              Print  NUM  lines  of  trailing context after matching lines.  Places a line containing a group separator (--)
              between contiguous groups of matches.  With the -o or --only-matching option, this has no effect and a warning
              is given.

       -B NUM, --before-context=NUM
              Print  NUM  lines  of  leading context before matching lines.  Places a line containing a group separator (--)
              between contiguous groups of matches.  With the -o or --only-matching option, this has no effect and a warning
              is given.

       -C NUM, -NUM, --context=NUM
              Print  NUM lines of output context.  Places a line containing a group separator (--) between contiguous groups
              of matches.  With the -o or --only-matching option, this has no effect and a warning is given.

   File and Directory Selection
       -a, --text
              Process a binary file as if it were text; this is equivalent to the --binary-files=text option.

       --binary-files=TYPE
              If the first few bytes of a file indicate that the file contains binary data, assume that the file is of  type
              TYPE.   By  default,  TYPE is binary, and grep normally outputs either a one-line message saying that a binary
              file matches, or no message if there is no match.  If TYPE is without-match, grep assumes that a  binary  file
              does  not  match; this is equivalent to the -I option.  If TYPE is text, grep processes a binary file as if it
              were text; this is equivalent to the  -a  option.   Warning:  grep  --binary-files=text  might  output  binary
              garbage,  which  can have nasty side effects if the output is a terminal and if the terminal driver interprets
              some of it as commands.

       -D ACTION, --devices=ACTION
              If an input file is a device, FIFO or socket, use ACTION to process it.  By default,  ACTION  is  read,  which
              means  that  devices  are  read  just as if they were ordinary files.  If ACTION is skip, devices are silently
              skipped.

       -d ACTION, --directories=ACTION
              If an input file is a directory, use ACTION to process it.  By default,  ACTION  is  read,  which  means  that
              directories  are  read  just  as  if  they  were  ordinary files.  If ACTION is skip, directories are silently
              skipped.  If ACTION is recurse, grep reads all files under each directory, recursively; this is equivalent  to
              the -r option.

       --exclude=GLOB
              Skip  files  whose base name matches GLOB (using wildcard matching).  A file-name glob can use *, ?, and [...]
              as wildcards, and \ to quote a wildcard or backslash character literally.

       --exclude-from=FILE
              Skip files whose base name matches any of the file-name globs read  from  FILE  (using  wildcard  matching  as
              described under --exclude).

       --exclude-dir=DIR
              Exclude directories matching the pattern DIR from recursive searches.

       -I     Process   a   binary   file   as   if   it   did  not  contain  matching  data;  this  is  equivalent  to  the
              --binary-files=without-match option.

       --include=GLOB
              Search only files whose base name matches GLOB (using wildcard matching as described under --exclude).

       -R, -r, --recursive
              Read all files under each directory, recursively; this is equivalent to the -d recurse option.

   Other Options
       --line-buffered
              Use line buffering on output.  This can cause a performance penalty.

       --mmap If possible, use the mmap(2) system call to read input, instead of the default read(2) system call.   In  some
              situations,  --mmap  yields  better performance.  However, --mmap can cause undefined behavior (including core
              dumps) if an input file shrinks while grep is operating, or if an I/O error occurs.

       -U, --binary
              Treat the file(s) as binary.  By default, under MS-DOS and MS-Windows, grep guesses the file type  by  looking
              at  the contents of the first 32KB read from the file.  If grep decides the file is a text file, it strips the
              CR characters from the original file contents (to make regular expressions  with  ^  and  $  work  correctly).
              Specifying  -U  overrules  this  guesswork,  causing all files to be read and passed to the matching mechanism
              verbatim; if the file is a text file with CR/LF pairs at the end of each line, this will  cause  some  regular
              expressions to fail.  This option has no effect on platforms other than MS-DOS and MS-Windows.

       -z, --null-data
              Treat  the  input  as  a  set  of lines, each terminated by a zero byte (the ASCII NUL character) instead of a
              newline.  Like the -Z or --null option, this option can  be  used  with  commands  like  sort  -z  to  process
              arbitrary file names.

REGULAR EXPRESSIONS
       A  regular  expression is a pattern that describes a set of strings.  Regular expressions are constructed analogously
       to arithmetic expressions, by using various operators to combine smaller expressions.

       grep understands three different versions of regular expression syntax: “basic” (BRE), “extended”  (ERE)  and  “perl”
       (PRCE). In GNU grep, there is no difference in available functionality between basic and extended syntaxes.  In other
       implementations, basic regular expressions are less powerful.  The following description applies to extended  regular
       expressions;  differences  for  basic  regular  expressions are summarized afterwards.  Perl regular expressions give
       additional functionality, and are documented in pcresyntax(3) and pcrepattern(3), but may not be available  on  every
       system.

       The  fundamental  building  blocks  are  the  regular  expressions  that  match a single character.  Most characters,
       including all letters and digits, are regular expressions that match themselves.   Any  meta-character  with  special
       meaning may be quoted by preceding it with a backslash.

       The period . matches any single character.

   Character Classes and Bracket Expressions
       A  bracket  expression is a list of characters enclosed by [ and ].  It matches any single character in that list; if
       the first character of the list is the caret ^ then it matches any character not  in  the  list.   For  example,  the
       regular expression [0123456789] matches any single digit.

       Within  a  bracket  expression,  a range expression consists of two characters separated by a hyphen.  It matches any
       single character that sorts between the  two  characters,  inclusive,  using  the  locale's  collating  sequence  and
       character set.  For example, in the default C locale, [a-d] is equivalent to [abcd].  Many locales sort characters in
       dictionary order, and in these locales [a-d] is typically not  equivalent  to  [abcd];  it  might  be  equivalent  to
       [aBbCcDd], for example.  To obtain the traditional interpretation of bracket expressions, you can use the C locale by
       setting the LC_ALL environment variable to the value C.

       Finally, certain named classes of characters are predefined within bracket expressions, as follows.  Their names  are
       self  explanatory,  and  they  are  [:alnum:],  [:alpha:],  [:cntrl:],  [:digit:],  [:graph:],  [:lower:], [:print:],
       [:punct:], [:space:], [:upper:], and [:xdigit:].  For example, [[:alnum:]] means the character class of  numbers  and
       letters  in  the  current  locale. In the C locale and ASCII character set encoding, this is the same as [0-9A-Za-z].
       (Note that the brackets in these class names are part of the symbolic names, and must be included in addition to  the
       brackets  delimiting  the  bracket  expression.)   Most  meta-characters  lose  their  special meaning inside bracket
       expressions.  To include a literal ] place it first in the list.  Similarly, to include a literal ^ place it anywhere
       but first.  Finally, to include a literal - place it last.

   Anchoring
       The  caret  ^ and the dollar sign $ are meta-characters that respectively match the empty string at the beginning and
       end of a line.

   The Backslash Character and Special Expressions
       The symbols \< and \> respectively match the empty string at the beginning and end of a word.  The symbol \b  matches
       the empty string at the edge of a word, and \B matches the empty string provided it's not at the edge of a word.  The
       symbol \w is a synonym for [_[:alnum:]] and \W is a synonym for [^_[:alnum:]].

   Repetition
       A regular expression may be followed by one of several repetition operators:
       ?      The preceding item is optional and matched at most once.
       *      The preceding item will be matched zero or more times.
       +      The preceding item will be matched one or more times.
       {n}    The preceding item is matched exactly n times.
       {n,}   The preceding item is matched n or more times.
       {n,m}  The preceding item is matched at least n times, but not more than m times.

   Concatenation
       Two regular expressions may  be  concatenated;  the  resulting  regular  expression  matches  any  string  formed  by
       concatenating two substrings that respectively match the concatenated expressions.

   Alternation
       Two  regular  expressions  may be joined by the infix operator |; the resulting regular expression matches any string
       matching either alternate expression.

   Precedence
       Repetition takes precedence over concatenation, which in turn takes precedence over alternation.  A whole  expression
       may be enclosed in parentheses to override these precedence rules and form a subexpression.

   Back References and Subexpressions
       The  back-reference  \n, where n is a single digit, matches the substring previously matched by the nth parenthesized
       subexpression of the regular expression.

   Basic vs Extended Regular Expressions
       In basic regular expressions the meta-characters ?, +, {, |, (, and ) lose their special  meaning;  instead  use  the
       backslashed versions \?, \+, \{, \|, \(, and \).

       Traditional  egrep  did  not  support  the  {  meta-character,  and some egrep implementations support \{ instead, so
       portable scripts should avoid { in grep -E patterns and should use [{] to match a literal {.

       GNU grep -E attempts to support traditional usage by assuming that { is not special if it would be the  start  of  an
       invalid  interval  specification.   For  example,  the  command grep -E '{1' searches for the two-character string {1
       instead of reporting a syntax error in the regular expression.  POSIX.2 allows this behavior  as  an  extension,  but
       portable scripts should avoid it.

ENVIRONMENT VARIABLES
       The behavior of grep is affected by the following environment variables.

       The  locale  for  category  LC_foo is specified by examining the three environment variables LC_ALL, LC_foo, LANG, in
       that order.  The first of these variables that is set specifies the locale.  For example, if LC_ALL is not  set,  but
       LC_MESSAGES is set to pt_BR, then the Brazilian Portuguese locale is used for the LC_MESSAGES category.  The C locale
       is used if none of these environment variables are set, if the locale catalog is not installed, or if  grep  was  not
       compiled with national language support (NLS).

       GREP_OPTIONS
              This  variable  specifies  default  options  to  be  placed in front of any explicit options.  For example, if
              GREP_OPTIONS is  '--binary-files=without-match  --directories=skip',  grep  behaves  as  if  the  two  options
              --binary-files=without-match  and  --directories=skip  had been specified before any explicit options.  Option
              specifications are separated by whitespace.  A backslash escapes the next character, so  it  can  be  used  to
              specify an option containing whitespace or a backslash.

       GREP_COLOR
              This  variable  specifies  the color used to highlight matched (non-empty) text.  It is deprecated in favor of
              GREP_COLORS, but still supported.  The mt, ms, and mc capabilities of GREP_COLORS have priority over  it.   It
              can only specify the color used to highlight the matching non-empty text in any matching line (a selected line
              when the -v command-line option is omitted, or a context line when -v is specified).  The  default  is  01;31,
              which means a bold red foreground text on the terminal's default background.

       GREP_COLORS
              Specifies  the  colors  and  other  attributes  used to highlight various parts of the output.  Its value is a
              colon-separated list of capabilities that defaults to  ms=01;31:mc=01;31:sl=:cx=:fn=35:ln=32:bn=32:se=36  with
              the rv and ne boolean capabilities omitted (i.e., false).  Supported capabilities are as follows.

              sl=    SGR  substring  for  whole  selected  lines  (i.e.,  matching  lines when the -v command-line option is
                     omitted, or non-matching lines when -v is specified).  If however the boolean rv capability and the  -v
                     command-line  option  are both specified, it applies to context matching lines instead.  The default is
                     empty (i.e., the terminal's default color pair).

              cx=    SGR substring for whole context lines (i.e., non-matching lines when  the  -v  command-line  option  is
                     omitted,  or  matching  lines  when  -v is specified).  If however the boolean rv capability and the -v
                     command-line option are both specified, it applies to selected non-matching lines instead.  The default
                     is empty (i.e., the terminal's default color pair).

              rv     Boolean  value  that reverses (swaps) the meanings of the sl= and cx= capabilities when the -v command-
                     line option is specified.  The default is false (i.e., the capability is omitted).

              mt=01;31
                     SGR substring for matching non-empty text in any matching line (i.e.,  a  selected  line  when  the  -v
                     command-line option is omitted, or a context line when -v is specified).  Setting this is equivalent to
                     setting both ms= and mc= at once to the same value.  The default is a bold red text foreground over the
                     current line background.

              ms=01;31
                     SGR  substring for matching non-empty text in a selected line.  (This is only used when the -v command-
                     line option is omitted.)  The effect of the sl= (or cx= if rv)  capability  remains  active  when  this
                     kicks in.  The default is a bold red text foreground over the current line background.

              mc=01;31
                     SGR  substring  for matching non-empty text in a context line.  (This is only used when the -v command-
                     line option is specified.)  The effect of the cx= (or sl= if rv) capability remains  active  when  this
                     kicks in.  The default is a bold red text foreground over the current line background.

              fn=35  SGR substring for file names prefixing any content line.  The default is a magenta text foreground over
                     the terminal's default background.

              ln=32  SGR substring for line numbers prefixing any content line.  The default is a green text foreground over
                     the terminal's default background.

              bn=32  SGR substring for byte offsets prefixing any content line.  The default is a green text foreground over
                     the terminal's default background.

              se=36  SGR substring for separators that are inserted between selected line fields (:), between  context  line
                     fields,  (-), and between groups of adjacent lines when nonzero context is specified (--).  The default
                     is a cyan text foreground over the terminal's default background.

              ne     Boolean value that prevents clearing to the end of line using Erase in Line (EL) to Right (\33[K)  each
                     time a colorized item ends.  This is needed on terminals on which EL is not supported.  It is otherwise
                     useful on terminals for which the back_color_erase (bce) boolean terminfo capability  does  not  apply,
                     when  the  chosen  highlight  colors do not affect the background, or when EL is too slow or causes too
                     much flicker.  The default is false (i.e., the capability is omitted).

              Note that boolean capabilities have no =...  part.  They are omitted (i.e., false) by default and become  true
              when specified.

              See  the  Select  Graphic  Rendition  (SGR) section in the documentation of the text terminal that is used for
              permitted values and their meaning as character attributes.  These substring values are  integers  in  decimal
              representation  and  can  be  concatenated  with  semicolons.  grep takes care of assembling the result into a
              complete SGR sequence (\33[...m).  Common values to concatenate include 1 for bold, 4  for  underline,  5  for
              blink,  7  for inverse, 39 for default foreground color, 30 to 37 for foreground colors, 90 to 97 for 16-color
              mode foreground colors, 38;5;0 to 38;5;255 for 88-color and 256-color modes foreground colors, 49 for  default
              background  color,  40 to 47 for background colors, 100 to 107 for 16-color mode background colors, and 48;5;0
              to 48;5;255 for 88-color and 256-color modes background colors.

       LC_ALL, LC_COLLATE, LANG
              These variables specify the locale for the LC_COLLATE category, which determines the collating  sequence  used
              to interpret range expressions like [a-z].

       LC_ALL, LC_CTYPE, LANG
              These  variables  specify the locale for the LC_CTYPE category, which determines the type of characters, e.g.,
              which characters are whitespace.

       LC_ALL, LC_MESSAGES, LANG
              These variables specify the locale for the LC_MESSAGES category, which determines the language that grep  uses
              for messages.  The default C locale uses American English messages.

       POSIXLY_CORRECT
              If  set,  grep  behaves  as  POSIX.2  requires; otherwise, grep behaves more like other GNU programs.  POSIX.2
              requires that options that follow file names must be treated as file  names;  by  default,  such  options  are
              permuted  to  the  front  of  the  operand  list  and  are  treated  as  options.  Also, POSIX.2 requires that
              unrecognized options be diagnosed as “illegal”, but since they are not really against the law the  default  is
              to diagnose them as “invalid”.  POSIXLY_CORRECT also disables _N_GNU_nonoption_argv_flags_, described below.

       _N_GNU_nonoption_argv_flags_
              (Here N is grep's numeric process ID.)  If the ith character of this environment variable's value is 1, do not
              consider the ith operand of grep to be an option, even if it appears to be one.  A shell can put this variable
              in  the  environment for each command it runs, specifying which operands are the results of file name wildcard
              expansion and therefore should not be treated as options.  This behavior is available  only  with  the  GNU  C
              library, and only when POSIXLY_CORRECT is not set.

EXIT STATUS
       The  exit  status  is  0 if selected lines are found, and 1 if not found.  If an error occurred the exit status is 2.
       (Note: POSIX error handling code should check for '2' or greater.)

COPYRIGHT
       Copyright 1998-2000, 2002, 2005-2012 Free Software Foundation, Inc.

       This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY  or
       FITNESS FOR A PARTICULAR PURPOSE.

BUGS
   Reporting Bugs
       Email     bug     reports     to     ,     a     mailing     list     whose     web     page     is
       .     grep's    Savannah    bug     tracker     is     located     at
       .

   Known Bugs
       Large  repetition  counts  in  the  {n,m} construct may cause grep to use lots of memory.  In addition, certain other
       obscure regular expressions require exponential time and space, and may cause grep to run out of memory.

       Back-references are very slow, and may require exponential time.

SEE ALSO
   Regular Manual Pages
       awk(1), cmp(1), diff(1), find(1), gzip(1), perl(1), sed(1), sort(1), xargs(1), zgrep(1), mmap(2),  read(2),  pcre(3),
       pcresyntax(3), pcrepattern(3), terminfo(5), glob(7), regex(7).

   POSIX Programmer's Manual Page
       grep(1p).

   TeXinfo Documentation
       The  full  documentation  for  grep  is  maintained  as a TeXinfo manual.  If the info and grep programs are properly
       installed at your site, the command

              info grep

       should give you access to the complete manual.

NOTES
       GNU's not Unix, but Unix is a beast; its plural form is Unixen.



User Commands                                           GNU grep 2.12                                                GREP(1)

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