grep(1)								      grep(1)



NAME
  grep, egrep, fgrep - Searches a file for patterns

SYNOPSIS

  grep [-E|-F] [-c|-l|-q] [-bhinsvwxy] [-pparagraph_separator] -e
  pattern_list [-e pattern_list]...  [-f pattern_file]...  [file...]

  grep [-E|-F] [-c|-l|-q] [-bhinsvwxy] [-pparagraph_separator] [-e
  pattern_list]...  -f pattern_file [-f pattern_file]...  [file...]

  grep [-E|-F] [-c|-l|-q] [-bhinsvwxy] [-pparagraph_separator] pattern_list
  [file...]

  The commands grep -E and grep -F are equivalent to the obsolescent commands
  egrep and fgrep, respectively.

  The grep command searches the specified files (standard input by default)
  for lines containing characters that match the specified patterns, and then
  writes matching lines to standard output.

FLAGS

  Although most flags can be combined, some combinations result in one flag
  overriding another. For example, if you specify -n and -l, the output
  includes filenames only (as specified by -l) and thus does not include line
  numbers (as specified by -n).

  -E  Treats patterns as extended regular expressions and is equivalent to
      the obsolescent egrep command.

  -F  Treats patterns as fixed strings and is equivalent to the obsolescent
      fgrep command.

  -b  Precedes each line by the block number on which it was found.  Use this
      flag to help find disk block numbers by context.

  -c  Displays only a count of matching lines.

  -e pattern_list
      Used to specify one or more patterns to match. If more than one pattern
      is specified in pattern_list, they must be separated by newline charac-
      ters (carriage returns). The -e flag is useful for specifying a pattern
      that begins with a - (dash).

  -f pattern_file
      Specifies a file that contains patterns to match, one per line.

  -h  Suppresses reporting of filenames when multiple files are processed.

  -i  Ignores the case of letters pattern matching; that is, uppercase and
      lowercase in the input are considered to be identical.

  -l  Lists only the name of each file containing matched lines. Each
      filename is listed only once; filenames are separated by newline char-
      acters.  grep returns (standard input) (or the local equivalent) in
      place of a filename if -l is specified with standard input.

  -n  Precedes each line with its relative line number in the file.

  -pparagraph_separator
      Displays the entire paragraph containing matched lines.  Paragraphs are
      delimited by paragraph separators, paragraph_separator, which are pat-
      terns in the same form as the search pattern.  Lines containing the
      paragraph separators are used only as separators; they are never
      included in the output.  The default paragraph separator is a blank
      line.

  -q  Suppresses all output except error messages. This is useful for check-
      ing status.

  -s  Suppresses error messages arising from non-existent or unreadable
      files. Other error messages are still displayed.

  -v  Displays all lines except those that match the specified pattern.	 Use-
      ful for filtering unwanted lines out of a file.

  -w  Matches only if the expression is found as a separate word in the text.
      A word is any string of alphanumeric characters (letters, numerals, and
      underscores) delimited by nonalphanumeric characters (punctuation or
      white space) or by the beginning or end of the line). See ex.

  -x  Displays a line only if the pattern matches the entire line.

  -y  Same as -i flag.

DESCRIPTION

  By default, the grep command treats a pattern as a basic regular expression
  (BRE). With the -E flag, the pattern is treated as an extended regular
  expression (ERE). With the -F flag, the pattern is considered a fixed
  string. See discussion of regular expressions, below.

  In the output of the grep command, a matched line is preceded with the name
  of the file in which it was found if you specify more than one file (except
  when the -h flag is specified).

  You are strongly encouraged to single quote patterns to protect them from
  unwanted shell substitutions. In some cases, such as in multiline pattern
  lists and subexpressions, quoting is essential. When using the C shell
  interactively, you must enter a backslash before terminating a line in a
  multiline pattern.

  Running grep on a non-text file (for example, an .o file) produces
  unpredictable results and is discouraged.

REGULAR EXPRESSIONS

  Regular expressions (RE's) provide a powerful way to specify patterns to
  search for in text files (or in the standard input). This section explains
  the rules for constructing such patterns.

  On DEC OSF/1 (and XPG4 conforming systems) there are two standard types of
  REs, and thus two sets of rules for building patterns. The two types of a
  regular expression that can be built by using these rules are termed either
  basic regular expression (BRE) or extended regular expression (ERE).	There
  is much in common between BREs and EREs, but there are important differ-
  ences as well.

  A variety of commands and utilities use one or the other type of RE, or
  both.	 Thus the rules described below are applicable in many contexts.
  Nonetheless, the grep command is used illustratively here.

  The term regular expression, or RE, is used when there is no need to dis-
  tinguish between BREs and EREs. The terms pattern and regular expression
  can be used interchangeably. The term match is used to describe a string in
  a file (or standard input) that is successfully specified by a pattern or
  RE. A pattern or an RE may also be referred to as a string. The matched
  string might also be termed a substring or a sequence (of characters).

  Simple REs match a single character. More complex REs are built from other
  REs as explained in the rules below. REs are defined recursively; for exam-
  ple, if you concatenate two REs, the resultant string is an RE.

  Regular Expression Concepts

  The concept of a character is generalized to the concept of a collating
  element. For many purposes, especially in English-speaking locales, the
  term collating element may be considered synonymous with character. Collat-
  ing elements are relevant to bracket expressions, and are discussed below.

  A collating element is the smallest unit used to determine how to order
  characters. They are necessary for languages that treat some strings as
  individual collating elements. For example, in Spanish, the strings ch and
  ll each are collating symbols (that is, the Spanish primary sort order is
  a, b, c, ch, d,...,k, l, ll, m,...).

  As an example, suppose we have a file test that contains these three lines:

       ab
       acbcbc
       12356

  The command  grep 'b' test  results in this output:

       ab
       acbcbc

  because the RE b, the pattern, matches the letter b in the first and second
  lines of the file, and there is no b in the third line. The RE c would
  match just the second line. The RE bc, built by concatenating the prior two
  REs, would match just the second line.

  There are two instances of bc in the second line, so the pattern matches
  the line. However, in using some of the rules that build REs, it is impor-
  tant to understand exactly what substrings are matched by a pattern.

  Those rules are given below, but for illustration, consider the RE c.*b.
  This pattern means match a string beginning with c, ending with b, and with
  any number of characters between, including none. Thus this pattern matches
  lines containing cb, cxb, and canythingb, for example.

  The search for a match starts at the beginning of a string and stops when
  the first sequence matching the pattern is found scanning from left to
  right. If there is more than one possible leftmost match, the longest match
  is used. For example, in the file test above, the pattern c.*b matches the
  second through third characters of the second line, and also the second
  through the fifth characters. The latter, being the longer, is the actual
  match.  However, a longer substring that is not the leftmost match is not a
  match.

  A null pattern will match any character, so the command

  grep '' test

  matches all three lines.

  A multicharacter collating element is considered a single character in the
  rules below that describe how to form a bracket expression, which matches a
  single character. However, when considering what the longest sequence is in
  a match involving a multicharacter collating element, the element counts
  not as one character but as the number of characters it matches.

  Pattern matching can be done in a case-insensitive manner. Case-insensitive
  processing permits matching of multicharacter collating elements as well as
  characters. For example, in

  grep -i '[[.Ch.]]' file

  the RE [[.Ch.]] would match ch, Ch, cH, or CH.  The notation is explained
  below.

  Some utilities that use regular expressions, including grep, process a file
  line by line. A line ends with a newline character. In general (but not
  with grep), the newline character is regarded as an ordinary character and
  both a period and a nonmatching list can match one. (See discussion below.)
  Some utilities, including grep, do not allow newline characters in a pat-
  tern to be matched.

  Basic Regular Expressions

  Basic regular expressions (BREs) are built by concatenating simpler BREs.
  BREs can be classified as those that can match a single character in the
  search string, and those that can match multiple characters.

  The following BREs match a single character (or collating element):

  An ordinary character, a special character preceded by a backslash, or a
  period (.), matches a single character. A bracket expression matches a sin-
  gle character or a single collating element. These terms are defined below.


  BRE Ordinary Characters

  Any character, except for those listed in the section ``BRE Special Charac-
  ters,'' below, is an ordinary character and is a BRE that matches itself.

  Except for the following, do not quote ordinary characters with a backslash
  (\):

    +  The characters (, ), { and }. The use of these characters quoted with
       backslashes is explained in the sections on subexpressions and inter-
       val expressions under the heading ``BREs Matching Multiple Charac-
       ters,'' below.

    +  The digits 1 to 9 inclusive. The use of these numerals quoted with
       backslashes is explained in the section on back-reference expressions
       under the heading ``BREs Matching Multiple Characters,'' below.

  You can not use a backslash to quote a character inside a bracket expres-
  sion; inside a bracket expression a backslash is an ordinary character.

  These characters, (, ), {, }, and 1 - 9 are considered ``ordinary charac-
  ters'' (see next section) because they do not have to be quoted with a
  backslash to match themselves as do ``special characters.''


  BRE Special Characters

  Some characters have special meaning when used in a BRE in some contexts,
  defined next. Outside such contexts, or in the context but quoted with a
  preceding backslash, these character have no special meaning, and each is a
  BRE that matches itself. The BRE special characters and contexts are:

  . [ \
      The period, left bracket, and backslash are special except when used in
      a bracket expression (discussed below). A pattern containing a [ that
      is not preceded by a backslash and is not part of a bracket expression
      is not valid.

  *   The asterisk is special except when used in a bracket expression, as
      the first character of a complete pattern (after an initial ^, if any),
      or as the first character of a subexpression (after an initial ^ if
      any);

  ^   The circumflex is special when used as an anchor or as the first char-
      acter of a bracket expression. These concepts are explained below.

  $   The dollar sign is special when used as an anchor.


  Periods in BREs

  A period (.), when used outside a bracket expression, is a BRE that matches
  any character.


  BRE Bracket Expression

  A non-null string enclosed in [ ] (brackets) is called a Bracket Expres-
  sion. It is a BRE that matches any single character (or collating element)
  in the enclosed string. For example, using the sample file test described
  above, the command

       grep '[a3][c5]' test

  outputs the second and third lines, acbcbc and 12356, because the two con-
  tiguous bracket expressions in the pattern match the substrings ac and 35
  in those lines.

  A bracket expression is either a matching list expression or a nonmatching
  list expression. It consists of one or more collating elements, collating
  symbols, equivalence classes, character classes or range expressions.

  The right bracket (]) loses its special meaning and represents itself in a
  bracket expression if it occurs first in the list (after an initial circum-
  flex (^), if any). Otherwise, it terminates the bracket expression, unless
  it appears in a collating symbol (such as [.].] ) or is the ending right
  bracket for a collating symbol, equivalence class, or character class.  The
  special characters . * [ \ (period, asterisk, left bracket and backslash)
  lose their special meanings within a bracket expression.

  The character sequences [., [=, and [: (left bracket followed by a period,
  equal sign, or colon) are special inside a bracket expression and are used
  to delimit collating symbols, equivalence class expressions and character
  class expressions. These symbols must be followed by a valid expression and
  the matching terminating sequence .], =], or :], as defined next.

  The rules follow for creating and using matching and nonmatching list
  expressions, collating symbol, equivalence class expression, character
  class expression, and range expression, in bracket expressions.

    +  A matching list expression, such as [a3] in the example above, speci-
       fies a list that matches any character or collating element in the
       list.  The first character in the list can not be a circumflex. [a3]
       matches either the character a or the character 3.

    +  A nonmatching list expression begins with a circumflex (^), and speci-
       fies a list that matches any character or collating element except for
       the expressions in the list after the leading circumflex. For example,
       [^abc] is a BRE that matches any character or collating element except
       the characters a, b or c. If the circumflex does not appear immedi-
       ately following the left bracket, it loses its special meaning.

    +  A collating symbol is a collating element enclosed within bracket-
       period ([. .]) delimiters. The concept is introduced above under the
       heading ``Regular Expression Concepts.''

       Multicharacter collating elements are represented as collating symbols
       to distinguish them from the individual characters in the collating
       symbol. For example, when using Spanish collation rules, [[.ch.]] is
       treated as a BRE matching the sequence ch, while [ch] is treated as an
       BRE matching c or h. In addition, [a-[.ch.]] matches a, b, c, and ch.
       (See ``range expressions'', below.) Collating symbols are valid only
       inside bracket expressions.

    +  An equivalence class expression specifies a set of collating elements
       that all sort to the same primary location. An equivalence class is
       enclosed in bracket-equal ([= =]) delimiters.

       An equivalence class generally is designed to deal with primary-
       secondary sorting; that is, for languages like French, that define
       groups of characters as sorting to the same primary location, and then
       having a tie-breaking, secondary sort.

       For example, if x, y, and z are collating elements that belong to the
       same equivalence class, then the bracket expressions [[=x=]a],
       [[=y=]a], and [[=z=]a] are equivalent to [xyza].(Here we use x, y, and
       z as variables representing characters in the same equivalence class;
       in a typical example, x might be the collating element e, and y and z
       the characters e with an acute accent and e with a grave accent.) If
       the collating element within [= =] delimiters does not belong to an
       equivalence class, the equivalence class expression is treated as a
       collating symbol, that is, the delimiters are ignored.

    +  A character class expression enclosed in bracket-colon [: :] delim-
       iters matches any of the set of characters in the named class. Members
       of each of the sets are determined by the current setting of the
       LC_CTYPE environment variable. The supported classes are: alpha,
       upper, lower, digit, alnum, xdigit, space, print, punct, graph, and
       cntrl. Here is an example of how to specify one of these classes:

       [[:lower:]]

       This matches any single lowercase character for the current locale.

    +  A range expression represents the set of collating elements that fall
       between two elements in the current collation sequence, inclusively.
       It is expressed as starting and ending points separated by a hyphen
       (-).  For example, the BRE 1[a-d]2, which includes the bracket expres-
       sion [a-d], containing the range expression a-d, represents a pattern
       that will match any of these strings: 1a2, 1b2, 1c2, and 1d2.

       Range expressions should not be used in portable applications because
       their behavior depends on collating sequences.

       A construction such as [a-d-g] is invalid.

       The hyphen character loses its special meaning in a bracket expression
       if it occurs first (after an initial ^, if any) or last, or as an end-
       ing range point in a range expression. For example, the expressions
       [-df] and [df-] are equivalent and match any of the characters d, f,
       or -. The expressions [^-df] and [^df-] are equivalent and match any
       characters except d, f and -; the expression [&--] matches any charac-
       ter between &, and - inclusive; the expression [--;] matches any of
       the characters between - and ; inclusive; and the expression [A--] is
       invalid, because A follows - in the collation sequence. A hyphen or
       right bracket may be represented as collating symbols, [.-.] or [.].],
       anywhere in a bracket expression; Otherwise, if both - and ] are
       required in a bracket expression, bracket must be first (after an
       optional initial ^) and the hyphen last.


  BREs Matching Multiple Characters

  The rules above describe how to construct a BRE that matches a single char-
  acter. In some of the examples above, patterns that match multiple charac-
  ters were given based on the intuitive concept of concatenation. This, and
  the other rules used to build BREs which match multiple characters from
  BREs matching single characters, follow.

    +  The concatenation of BREs matches the concatenation of the strings
       matched by each component of the BRE.

    +  A subexpression can be defined within a BRE by enclosing it between
       the character pairs \( and \). Such a subexpression matches whatever
       it would have matched without the \( and \).

       Up to nine subexpressions are saved into numbered holding spaces.
       Counting from left to right on the line, the first pattern saved is
       placed in the first holding space, the second pattern is placed in the
       second holding space, and so on.

       The character sequence \n, called a back-reference expression, matches
       the nth saved pattern, which is in the nth holding space. (The value
       of n is a digit, 1-9.) Thus, the pattern:

       \(a\)\(b\)c\2\1

       matches the string abcba. You can nest patterns to be saved in holding
       spaces. Whether the enclosed patterns are nested or are in a series,
       \n refers to the nth occurrence, counting from the left, of the delim-
       iting characters \). In utilities that have replacement as well as
       search patterns, you can use \n expressions in the replacement strings
       as well as in the search patterns.

       A back-reference expression is invalid if less than n subexpressions
       precede the \n. Finally, any number of subexpressions are allowed in a
       search pattern even though the number of back-reference expressions is
       limited to nine.

    +  If a BRE x matches a single character, or is a subexpression or a
       back-reference, then the pattern x* (x followed by an asterisk),
       matches zero or more occurrences of the character that the BRE x
       matches. For example, this pattern:
	    ab*cd

       matches each of these strings:
	    acd
	    abcd
	    abbcd
	    abbbcd

       but not this string:
	    abd

    +  A BRE that matches a single character, or that is a subexpression or a
       back-reference, followed by an interval expression of the format
       \{i\}, \{i,\} or \{i,j\}, matches what repeated consecutive
       occurrences of the BRE would match. Such a BRE followed by:

       \{i\}
	   matches exactly i occurrences of the character matched by the BRE

       \{i,\}
	   matches at least i occurrences of the character matched by the BRE

       \{i,j\}
	   matches any number of occurrences of the character matched by the
	   BRE from i to j, inclusive.

       The values of i and j must be integers in the range 0 <= i <= j <=
       255. Whenever a choice exists, the pattern matches as many occurrences
       as possible.

       Note that if i is 0 (zero), the interval expression is equivalent to
       the null BRE.


  BRE Expression Anchoring - Restricting What Patterns Match

  A pattern (an entire BRE) can be restricted to match from the beginning of
  a line, restricted to match up to the end of the line, or restricted to
  match the entire line. This is done by anchoring the search pattern.

    +  A ^ (circumflex) at the beginning of an expression or subexpression
       causes the pattern to match only a string that begins in the first
       character position on a line. For example, the pattern ^bc matches bc
       in the line bcdef but doesn't match bc in abcdef.  The subexpression
       \(^bc\) also matches bcdef.

    +  A $ (dollar sign) at the end of a pattern causes that pattern to match
       only if the last matched character is the last character (not includ-
       ing the newline character) on a line.

    +  The construction ^pattern$ restricts the pattern to matching only an
       entire line. For example, the BRE ^abcd$ matches lines containing the
       string abcd, where a is the first character on the line and d the
       last.


  BRE Precedence

  The order of precedence, for high to low, is as shown in the following
  table:
  ________________________________________________________
  collation-related bracket symbols    [= =] [: :] [. .]
  ________________________________________________________
  escaped characters		      \
  ________________________________________________________
  bracket expressions		      [ ]
  ________________________________________________________
  subexpressions/back-references      \( \) \n
  ________________________________________________________
  single-character duplication	      * \{i,j\}
  ________________________________________________________
  concatenation
  ________________________________________________________
  anchoring			      ^ $
  ________________________________________________________

  Extended Regular Expressions

  Like BREs, extended regular expressions (EREs) are built by concatenating
  simpler EREs. EREs can be classified as those that can match a single
  character, and those that can match multiple characters.

  An ERE ordinary character, an ERE special character preceded by a
  backslash, or a period matches a single character. A bracket expression
  matches a single character or a single collating element. An ERE matching a
  single character enclosed in parentheses (a group) matches the same strings
  as the ERE without parentheses.


  ERE Ordinary Characters

  Any character, except for special characters listed below, is an ordinary
  character and is an ERE that matches itself.


  ERE Special Characters

  Some characters have special meaning when used in a ERE in some contexts,
  defined next. Outside such contexts, or in the context but quoted with a
  preceding backslash, these character have no special meaning, and each is a
  ERE that matches itself. The ERE special characters and contexts are:

  . [ \ (
      The period, left bracket, backslash and left parenthesis are special
      except when used in a bracket expression. Outside a bracket expression,
      do not use a left parenthesis, (, unless it is quoted with a backslash,
      \(.

  )   The right parenthesis is special when matched with a preceding left
      parenthesis, outside a bracket expression. To search for the string (),
      use the quoted form \().

  * + ? {
      The asterisk, plus sign, question mark, and left brace are special
      except when used in a bracket expression. Outside of a bracket expres-
      sion, it is invalid to use any of them as the first character in an
      ERE, or immediately following a vertical line, a circumflex, or a left
      parenthesis. It is invalid to use a left brace that is not part of an
      interval expression. (Of course, quoting with a backslash removes such
      invalidity.)

  |   The vertical line is special except when used in a bracket expression.
      It is invalid to use a vertical line first or last in an ERE, or
      immediately following another vertical line or a left parenthesis, or
      immediately preceding a right parenthesis.

  ^   The circumflex is special when used as an anchor or as the first char-
      acter of a bracket expression.

  $   The dollar sign is special when used as an anchor.


  Periods in EREs

  A period (.), when used outside a bracket expression, is an ERE that
  matches any character.


  ERE Bracket Expression

  The rules for ERE Bracket Expressions are the same as for the BRE bracket
  expressions discussed above.


  EREs Matching Multiple Characters

  The rules above describe how to construct an ERE that matches a single
  character. The rules used to build EREs which match multiple characters
  from EREs matching single characters follow.

    +  A concatenation of EREs matches the concatenation of the strings
       matched by each component of the ERE. A concatenation of EREs enclosed
       in parentheses, matches whatever the concatenation without the
       parentheses matches. For example, both EREs ab and (ab) match the
       second and third characters of the string cabcdabc.

    +  An ERE matching a single character or an ERE enclosed in parentheses
       followed by the special character plus sign (+) matches what one or
       more consecutive occurrences of the ERE would match. For example, the
       ERE (ab)a+ matches the second to sixth character in the string
       cabaaabc and c(ab)+ matches the first to seventh characters in the
       string cabababc.

    +  An ERE matching a single character or an ERE enclosed in parentheses
       followed by the special character asterisk (*) matches what zero or
       more consecutive occurrences of the ERE would match. For example, the
       ERE b*c matches the first character in the string cabbbcde, and the
       ERE c*de matches the second to sixth characters in the string dcccdec.
       The EREs [cd]+ and [cd][cd]* are equivalent and [cd]* and [cd][cd] are
       equivalent when matching the string cd.

    +  An ERE matching a single character or an ERE enclosed in parentheses
       followed by the special character question mark (?) matches what zero
       or one consecutive occurrence of the ERE would match. For example, the
       ERE c?d matches the third character in the string abdbcccde.

    +  An ERE matching a single character or an ERE enclosed in parentheses
       followed by an interval expression of the format {i}, {i,}, or {i,j},
       matches what repeated consecutive occurrences of the ERE would match.
       The rules for matching are the same as for BRE interval expressions
       (discussed above) except for the notational difference.

       For example, the ERE d{3} matches characters eight through 10 in the
       string abcbcbcddddde and the ERE (bc){2,} matches characters two to
       seven.


  ERE Alternation

  If x and y are EREs, then x|y is an ERE that matches any string that is
  matched by either x or y. For example, the ERE ((cd)|e)b matches the string
  cdb and the string eb.  Single characters, or expressions matching single
  characters, separated by the vertical bar and enclosed in parentheses,
  match a single character.


  ERE Expression Anchoring

  ERE anchoring is the same as BRE anchoring, discussed above.


  ERE Precedence

  The order of precedence, for high to low, is as shown in the following
  table:
  ________________________________________________________
  collation-related bracket symbols    [= =] [: :] [. .]
  ________________________________________________________
  escaped characters		      \
  ________________________________________________________
  bracket expression		      [ ]
  ________________________________________________________
  grouping			      ( )
  ________________________________________________________
  single-character duplication	      * + ? {i,j}
  ________________________________________________________
  concatenation
  ________________________________________________________
  anchoring			      ^ $
  ________________________________________________________
  alternation			      |
  ________________________________________________________

  For example, the pattern ab|cd is the same as (ab)|(cd) and is not
  equivalent to a(b|c)d.

EXAMPLES

   1.  To search several C-language source files for the pattern strcpy,
       enter:
	    grep  'strcpy'  *.c

       This searches for the string strcpy in all files in the current direc-
       tory with names ending in .c.

   2.  To count the number of lines that match a pattern, enter:
	    grep -F -c	'{'  pgm.c
	    grep -F -c	'}'  pgm.c

       This displays the number of lines in pgm.c that contain left and right
       braces.

       If you do not put more than one { or } on a line in your C programs,
       and if the braces are properly balanced, then the two numbers
       displayed will be the same. If the numbers are not the same, then you
       can display the lines that contain braces with the command:
	    grep  -n  -E  '\{|}'  pgm.c

   3.  To display all lines in a file that begin with an ASCII letter, enter:
	    grep  '^[a-zA-Z]'  pgm.s

       Note that because grep -F searches only for fixed strings and does not
       use regular expressions such as bracket expressions or anchoring, the
       following command causes grep to search only for the literal string
       ^[a-zA-Z] in pgm.s:
	    grep  -F  '^[a-zA-Z]'  pgm.s

   4.  To display all lines that contain ASCII letters in parentheses or
       digits in parentheses (with spaces optionally preceding and following
       the letters or digits), but not letter-digit combinations in
       parentheses, enter:
	    grep  -E  '\(  *([a-zA-Z]*|[0-9]*)	*\)'  my.txt

       This command displays lines in my.txt such as (	783902) or (y), but
       not (alpha19c).

       Note that with grep -E, \( and \) match parentheses in the text and (
       and ) are special characters that group parts of the pattern.  With
       grep without the -E flag, the reverse is true; use ( and ) to match
       parentheses and \( and \) to group characters.

   5.  To display all lines that do not match a pattern, enter:
	    grep  -v  '^#'

       This displays all lines that do not begin with a # (number sign).

   6.  To display the names of files that contain a pattern, enter:
	    grep  -F -l	 'rose'	 *.list

       This searches the files in the current directory that end with .list
       and displays the names of those files that contain at least one line
       containing the string rose.

   7.  To display all lines that contain uppercase characters, enter:
	    grep [[:upper:]] pgm.s

   8.  To display all lines that begin with a range of characters that
       includes a multicharacter collating symbol, enter:
	    grep '^[a-[.ch.]]' pgm.s

       With your locale set to a Spanish locale, this command matches all
       lines that begin with a, b, c, or ch.

EXIT VALUES

  The exit values of the grep command are:

  0   A match was found.

  1   No match was found.

  2   A syntax error was found or a file was inaccessible, even if matches
      were found.

RELATED INFORMATION

  Commands:  ed(1)/red(1), ex(1), sed(1), sh(1).