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This page displays the COHERENT manpage for egrep [Extended pattern search].
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egrep -- Command Extended pattern search egrep [-Abcefhily] [pattern] [file ...] egrep is an extended and faster version of grep. It searches each file for occurrences of pattern (also called a regular expression). If no file is specified, it searches the standard input. Normally, it prints each line matching the pattern. Wildcards The simplest patterns accepted by egrep are ordinary alphanumeric strings. Like ed, egrep can also process patterns that include the following wildcard characters: ^ Match beginning of line, unless it appears immediately after `[' (see below). $ Match end of line. * Match zero or more repetitions of preceding character. . Match any character except newline. [chars] Match any one of the enclosed chars. Ranges of letters or digits may be indicated using `-'. [^chars] Match any character except one of the enclosed chars. Ranges of letters or digits may be indicated using `-'. \c Disregard special meaning of character c. Metacharacters In addition, egrep accepts the following additional metacharacters: | Match the preceding pattern or the following pattern. For example, the pattern cat|dog matches either cat or dog. A newline within the pattern has the same meaning as `|'. + Match one or more occurrences of the immediately preceding pattern element; it works like `*', except it matches at least one occurrence instead of zero or more occurrences. ? Match zero or one occurrence of the preceding element of the pattern. (...) Parentheses may be used to group patterns. For example, (Ivan)+ matches a sequence of one or more occurrences of the four letters `I' `v' `a' or `n'. Because the metacharacters `*', `?', `$', `(', `)', `[', `]', and `|' are also special to the shell, patterns that contain those literal characters must be quoted by enclosing pattern within apostrophes. Options The following lists the available options: -A Write all lines in which expression is found into a temporary file. Then, call COHERENT with its error option to process the source file, with the contents of the temporary file serving as an ``error'' list. This option resembles the -A option to the cc command, and lets you build a COHERENT script to make systematic changes to the source file. To exit COHERENT and prevent egrep from searching further, <ctrl- U> <ctrl-X> <ctrl-C>. Unlike cgrep, egrep only matches patterns that are on a single line. Some systems have a context grep cgrep) that works like egrep but displays lines found in context. The COHERENT egrep -A not only displays lines in context, via COHERENT, it lets you edit them. -b With each output line, print the block number in which the line started (used to search file systems). -c Print how many lines match, rather than the lines themselves. -e The next argument is pattern (useful if the pattern starts with `-'). -f The next argument is a file that contains a list of patterns separated by newlines; there is no pattern argument. -h When more than one file is specified, output lines are normally accompanied by the file name; -h suppresses this. -i Ignore case when matches alphabetic letter in pattern. egrep takes case into account, even with this option, when you prefix a letter in pattern with `\'. -l Print the name of each file that contains the string, rather than the lines themselves. This is useful when you are constructing a batch file. -n When a line is printed, also print its number within the file. -s Suppress all output, just return exit status. -v Print a line only if the pattern is not found in the line. -y Lower-case letters in the pattern match only upper-case letters on the input lines. A letter escaped with `\' in the pattern must be matched in exactly that case. Limits The COHERENT implementation of egrep sets the following limits on input and output: Characters per input record 512 Characters per output record 512 Characters per field 512 See Also awk, cgrep, commands, ed, expr, grep, lex, sed Diagnostics egrep returns an exit status of zero for success, one for no matches, and two for error. Notes For matching patterns in C programs, the command cgrep is preferred, because it is optimized to recognize C-style expressions. Besides the difference in the range of patterns allowed, egrep uses a deterministic finite automaton (DFA) for the search. It builds the DFA dynamically, so it begins doing useful work immediately. This means that egrep is is much faster than grep, often by more than an order of magnitude, and is considerably faster than earlier pattern-searching commands, on almost any length of file.