grep vs egrep

The Three Musketeers of text processing under LinuxThe first sword grep, Egrep, Fgrep: Text Search tool; Search operations on given text based on "pattern";The second Sword Sed:stream editor, stream editor, line editing tools, text editing tools;Third Sword Awk:gnu awk, text formatting tool; Text Report Generator;Today, we mainly explain the first sword:grep family:grep: Supports the use of basic regular ex

Tags: multiple grep linux that do not contain file auto grep-e expression filesGrep is also a tool found in Linux, operations, programmers must master theThe following parameters are described for grep:--colorKey marker matches to itemgrep "A word" datafile--color=auto-EGREP uses regular expressions, or it can be used

I. Regular Expressions The use of a system is not only the installation, debugging, and maintenance of software, but also the optimization and reform of the existing environment, in linux, we always encounter many descriptions of parameters.

specified by POSIX are explicitly labeled as convenient for POSIX portability programming. There are a few options to be compatible with older grep versions. There are several additional options to control which variant 'grep' match engine is used (Note: fgrep/grep/egrep ). 2.1.1 Generic Program Information '--help'Ou

Egrep function description: the egrep command and the grep command have the-E flag, except for the difference in the error message and the use of the message and the function of the-s flag. Use the egrep command to search for one or more files. the prompt can be an extension rule expression symbol. the extension rule e

Recalling the previous chapter, in the previous chapter we described the Text Processing tool grep command, which is performed by the user according to the specified "pattern" for row matching, the default is greedy mode, the matching results are printed to standard output, and the regular expression is written by a group of special characters, Some of these characters do not represent the original literal meaning, but for the function of control or w

gawkGrep:global search REgular expression and Print out of the line.Function: Text Search tool, according to user-specified "pattern" line to search for target text, print the matching line;Pattern: The filter condition written by metacharacters and text characters of regular expressions;Metacharacters: A character does not represent its literal meaning, but is used to denote a wildcard or control function;Divided into two categories:Basic Regular Expressions: BREExtended Regular expression: ER

I. Introduction of EGREPEgrep is an expanded version of grep, which improves the operation of many traditional grep that cannot or is inconvenient, and uses the same usage as grep.Comparison of Egrep with grep:1. Not supported under grep? With + These two special characters,

above example, ooo* means Oo, ooo, oooo ... or more O.In the example above,. * Represents 0 or more arbitrary characters, and a blank line is included, which matches all the lines in the/etc/passwd file.Nine, specify the characters to filter out the number of wordsDescription: The symbol {}, which is a number inside, indicating the number of times the preceding character is to be repeated .Note (focus): {} need to add the escape character \. In addition, the use of "{}" can also represent a ran

Linux regular expressions-Basic Regular Expressions (based on grep) Linux regular expression: In short, regular expressions are a set of rules and methods defined to process a large number of strings. For example, suppose @ represents 123456 ,! Represents abcde. the system administrator can quickly filter, replace, or output the desired characters by defining these special symbols. Notes for using regular expressions: 1. linux regular expressions are

Linux Regular Expressions:In short, a regular expression is a set of rules and methods that are defined for processing a large number of strings, such as assuming @ represents 123456,! for ABCDE. By defining these special symbols, the system administrator can quickly filter, replace, or output the required characters.Considerations for using Regular expressions:1.linux regular is usually handled by the behavioral unit.2.alias grep= '

An extended regular expression:An extended regular expression, as the name implies, is an extension of the regular expression that accepts all regular expressions and expands on grep. such as: Support or expression a|bCharacter matching:.: matches any single character []: matches any single character in the specified range [^]: matches any single character number outside the specified range: *: any time?: 0 or 1 times, indicating its left character is

Linux egrep file content search tool and extended regular expression detailedegrep Command : Search for text based on patterns (matching criteria for text characters and extended Regular expression meta-character combinations)and displays the line of text that conforms to the pattern.Format: egrep [option] Match condition text nameegrep equals Grep-e .Option:-I:

containing boo, you can use the-w option to forcibly output only the rows that contain the entire word (LCTT: that is, the two sides of the string are English word delimiters, such as spaces and punctuation marks, it is not applicable to Chinese languages without break characters .). $ grep -w "boo" file Use the grep command to search for two different words The egrep