Regex 101: Difference between revisions
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Created page with "=Testing= echo "My stuff" | grep "^My" =Examples= =Starts with= <syntaxhighlight lang="regex"> echo "A" |grep "^A" echo "AAAAAAAAAAA" |grep "^A" </syntaxhighlight>" |
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=Testing= | =Testing= | ||
echo "My stuff" | grep "^My" | echo "My stuff" | grep "^My" | ||
=Examples= | ==Examples== | ||
=Starts with= | ==Starts with== | ||
<syntaxhighlight lang=" | <syntaxhighlight lang="bash"> | ||
echo "A" |grep "^A" | echo "A" |grep "^A" | ||
echo "AAAAAAAAAAA" |grep "^A" | echo "AAAAAAAAAAA" |grep "^A" | ||
</syntaxhighlight> | |||
==Starts with any number of As and Ends With== | |||
<syntaxhighlight lang="bash"> | |||
echo "AAAAAAAAAAAB" |grep "^A*B$ | |||
</syntaxhighlight> | |||
==Word Boundries== | |||
Was not sure what this meant but what it means is a word in a sentence e.g. quick brown fox so this would be a match | |||
<syntaxhighlight lang="bash"> | |||
echo "quick brown fox jumps over" |grep "\bfox\b" | |||
</syntaxhighlight> | |||
And this would not be a match | |||
<syntaxhighlight lang="bash"> | |||
echo "quick brownfoxjumps over" |grep "\bfox\b" | |||
echo "quick brown foxjumps over" |grep "\bfox\b" | |||
echo "quick brownfox jumps over" |grep "\bfox\b" | |||
</syntaxhighlight> | |||
=Match Start and End with anything in the middle= | |||
Ran into trouble with this as I found grep does not work like the examples<br> | |||
^Me matches beginning | |||
s+(.*?)\s+ matches everything from space to last space | |||
Fred$ makes sure the phrase ends in Fred | |||
Using grep fails, using egrep works | |||
<syntaxhighlight lang="bash"> | |||
echo "Me grindurr 9 51 19 3 7 1 2 2 Fred" |egrep "^Me\s+(.*?)\s+Fred$" | |||
</syntaxhighlight> | |||
In egrep (.*?) matches any character. It turned out the \s+ was the problem and this works | |||
<syntaxhighlight lang="bash"> | |||
echo "Me grindurr 9 51 19 3 7 1 2 2 Fred" |egrep "^Me\s(.*?)\sFred$" | |||
</syntaxhighlight> | </syntaxhighlight> | ||
Latest revision as of 03:49, 11 April 2021
Testing
echo "My stuff" | grep "^My"
Examples
Starts with
echo "A" |grep "^A"
echo "AAAAAAAAAAA" |grep "^A"
Starts with any number of As and Ends With
echo "AAAAAAAAAAAB" |grep "^A*B$
Word Boundries
Was not sure what this meant but what it means is a word in a sentence e.g. quick brown fox so this would be a match
echo "quick brown fox jumps over" |grep "\bfox\b"
And this would not be a match
echo "quick brownfoxjumps over" |grep "\bfox\b"
echo "quick brown foxjumps over" |grep "\bfox\b"
echo "quick brownfox jumps over" |grep "\bfox\b"
Match Start and End with anything in the middle
Ran into trouble with this as I found grep does not work like the examples
^Me matches beginning s+(.*?)\s+ matches everything from space to last space Fred$ makes sure the phrase ends in Fred
Using grep fails, using egrep works
echo "Me grindurr 9 51 19 3 7 1 2 2 Fred" |egrep "^Me\s+(.*?)\s+Fred$"
In egrep (.*?) matches any character. It turned out the \s+ was the problem and this works
echo "Me grindurr 9 51 19 3 7 1 2 2 Fred" |egrep "^Me\s(.*?)\sFred$"