Regular Expressions - Revision history

Leo: /* Usage with sed */

2022-01-04T19:40:31Z

Usage with sed

← Older revision		Revision as of 19:40, 4 January 2022
Line 109:		Line 109:

	=== Usage with sed ===		=== Usage with sed ===
	When using <code>sed</code>, you need to escape <code>[]</code> ~~and~~ <code>{}</code>. For example:		When using <code>sed</code>, you need to escape special characters like <code>()</code>, <code>{}</code>, and <code>/</code>. For example:
	{{Highlight		{{Highlight
	\| code = cat file {{!}} sed 's/$9[0-9]\{1\}%$/<strong style="color:orange">\1<\/strong>/'		\| code = $ cat file {{!}} sed 's/$9[0-9]\{1\}%$/<strong style="color:orange">\1<\/strong>/'
	\| lang = terminal		\| lang = terminal
	}}		}}
	[[Category:Guides]]		[[Category:Guides]]

Leo at 19:39, 4 January 2022

2022-01-04T19:39:33Z

← Older revision		Revision as of 19:39, 4 January 2022
Line 1:		Line 1:
	~~<br />~~		A cheat sheet with regular expressions.

	== Special characters and their meanings ==		== Special characters and their meanings ==
Line 105:		Line 105:
	\|Any character not part of the character classes: <code>[:upper:], [:lower:], [:alpha:], [:digit:], [:punct:], [:graph:], [:print:], [:xdigit:]</code><br />		\|Any character not part of the character classes: <code>[:upper:], [:lower:], [:alpha:], [:digit:], [:punct:], [:graph:], [:print:], [:xdigit:]</code><br />
	\|}		\|}

			== Other notes ==

			=== Usage with sed ===
			When using <code>sed</code>, you need to escape <code>[]</code> and <code>{}</code>. For example:
			{{Highlight
			\| code = cat file {{!}} sed 's/$9[0-9]\{1\}%$/<strong style="color:orange">\1<\/strong>/'
			\| lang = terminal
			}}
	[[Category:Guides]]		[[Category:Guides]]

Leo: Added category

2021-12-30T02:09:19Z

Added category

← Older revision		Revision as of 02:09, 30 December 2021
Line 105:		Line 105:
	\|Any character not part of the character classes: <code>[:upper:], [:lower:], [:alpha:], [:digit:], [:punct:], [:graph:], [:print:], [:xdigit:]</code><br />		\|Any character not part of the character classes: <code>[:upper:], [:lower:], [:alpha:], [:digit:], [:punct:], [:graph:], [:print:], [:xdigit:]</code><br />
	\|}		\|}
			[[Category:Guides]]

Leo: Created page with "
== Special characters and their meanings == {| class="wikitable" !Character !Meaning !Example |- |`*` |Match '''zero, one or more''' of the previous |`..."`


2021-12-12T06:18:32Z
Created page with "<br />  == Special characters and their meanings == {| class="wikitable" !Character !Meaning !Example |- |<code>*</code> |Match '''zero, one or more''' of the previous |<code>..."
New page
<br />



== Special characters and their meanings ==

{| class="wikitable"

!Character

!Meaning

!Example

|-

|<code>*</code>

|Match '''zero, one or more''' of the previous

|<code>Ca*</code> matches <code>C</code> or <code>Ca</code> or <code>Caaaa</code>

|-

|<code>?</code>

|Match '''zero or one''' of the previous

|<code>Ca?</code> matches <code>C</code> or <code>Ca</code>, but not <code>Caaa</code>

|-

|<code>+</code>

|Match '''one or more''' of the previous

|<code>Ca*</code> matches <code>Ca</code> or <code>Caaaa</code>, but not <code>C</code>

|-

|<code>\</code>

|Used to '''escape''' a special characters <code><nowiki>\ ? ( ) [ ] |</nowiki></code>

|<code>C:\\</code> matches <code>C:\</code>

|-

|<code>.</code>

|Wildcard character, matches '''any''' character

|<code>Ca.*</code> matches <code>Canada</code>, <code>Can't</code>, <code>Caught</code>, etc.

|-

|<code>( )</code>

|'''Group''' characters

|See example for <code><nowiki>|</nowiki></code>. Can also be used for replacing text with <code>\1</code>, <code>\2</code>, etc.

|-

|<code>[ ]</code>

|Matches a '''range''' of characters

|<code>[cbf]ar</code> matches <code>car</code>, <code>bar</code>, <code>far</code>.

<code>[0-9]+</code> matches any integer.

<code>[a-zA-Z]</code> matches ASCII letters a-z (upper and lower case)

<code>[^0-9]</code> matches any character not 0-9

|-

|<code><nowiki>|</nowiki></code>

|Matches previous '''OR''' next character/group

|<code><nowiki>(Mon|Tues)day</nowiki></code> matches "Monday" or "Tuesday"

|-

|<code>{ }</code>

|Matches a specified '''number of occurrences''' of the previous

|<code>[a-z]{3}</code> matches any 3 character string using characters a-z. Eg. <code>abc</code>, <code>xyz</code>.

<code>[0-9]{2,4}</code> matches any 2 to 4 digit number. Eg. 23, 349, 5934.

<code>[a-z0-9]{2,}</code> matches any alpha-numeric lowercase string longer than 2 characters. Eg. <code>a9</code>, <code>c1cd</code>...

|-

|<code>^</code>

|'''Beginning''' of a string or '''negation''' in a range.

|<code>^http:\/\/</code> matches anything starting with <code>http://</code>

<code>[^0-9]</code> matches any character not 0-9.

|-

|<code>$</code>

|'''End''' of a string.

|<code>\.exe$</code> matches anything ending with <code>.exe</code>

|}



== POSIX character classes ==

{| class="wikitable"

!Character Class

!Meaning

|-

|<code>[:alpha:]</code>

|Any letter, <code>[A-Za-z]</code>

|-

|<code>[:upper:]</code>

|Any uppercase letter, <code>[A-Z]</code>

|-

|<code>[:lower:]</code>

|Any lowercase letter, <code>[a-z]</code>

|-

|<code>[:digit:]</code>

|Any digit, <code>[0-9]</code>

|-

|<code>[:alnum:]</code>

|Any alphanumeric character, <code>[A-Za-z0-9]</code>

|-

|<code>[:xdigit:]</code>

|Any hexadecimal digit, <code>[0-9A-Fa-f]</code>

|-

|<code>[:space:]</code>

|A tab, new line, vertical tab, form feed, carriage return, or space

|-

|<code>[:blank:]</code>

|A space or a tab.

|-

|<code>[:print:]</code>

|Any printable character

|-

|<code>[:punct:]</code>

|Any punctuation character: <code><nowiki>! ' # S % & ' ( ) * + , - . / : ; < = > ? @ [ / ] ^ _ { | } ~</nowiki></code>

|-

|<code>[:graph:]</code>

|Any character defined as a printable character except those defined as part of the space character class

|-

|<code>[:word:]</code>

|Continuous string of alphanumeric characters and underscores.

|-

|<code>[:ascii:]</code>

|ASCII characters, in the range: 0-127

|-

|<code>[:cntrl:]</code>

|Any character not part of the character classes: <code>[:upper:], [:lower:], [:alpha:], [:digit:], [:punct:], [:graph:], [:print:], [:xdigit:]</code><br />

|}

Regular Expressions - Revision history

Leo: /* Usage with sed */

Leo at 19:39, 4 January 2022

Leo: Added category

Leo: Created page with " == Special characters and their meanings == {| class="wikitable" !Character !Meaning !Example |- |* |Match '''zero, one or more''' of the previous |..."

Leo: Created page with "
== Special characters and their meanings == {| class="wikitable" !Character !Meaning !Example |- |`*` |Match '''zero, one or more''' of the previous |`..."`