How to do a non-greedy match in grep

Question

I want to grep the shortest match and the pattern should be something like    lt car     model BMW     gt               lt  car gt        means any character and the input is multiple lines

User · Answer

The short answer is using the next regular expression:

(?s)<car .*? model=BMW .*?>.*?</car>

(?s) - this makes a match across multiline
.*? - matches any character, a number of times in a lazy way (minimal match)

A (little) more complicated answer is:

(?s)<([a-z\-_0-9]+?) .*? model=BMW .*?>.*?</\1>

This will makes possible to match car1 and car2 in the following text

<car1 ... model=BMW ...>
...
...
...
</car1>
<car2 ... model=BMW ...>
...
...
...
</car2>

(..) represents a capturing group
\1 in this context matches the sametext as most recently matched by capturing group number 1

User · Answer

You re looking for a non-greedy  or lazy  match  To get a non-greedy match in regular expressions you need to use the modifier   after the quantifier  For example you can change    to       By default grep doesn t support non-greedy modifiers  but you can use grep -P to use the Perl syntax

User · Answer

Actualy the     only works in perl  I am not sure what the equivalent grep extended regexp syntax would be  Fortunately you can use perl syntax with grep so grep -P would work but grep -E which is same as egrep would not work  it would be greedy    See also  http   blog vinceliu com 2008 02 non-greedy-regular-expression-matching html

User · Answer

I know that its a bit of a dead post but I just noticed that this works  It removed both clean-up and cleanup from my output     gt  grep -v -e  clean -  up   gt  grep --version grep  GNU grep  2 20

User · Answer

My grep that works after trying out stuff in this thread   echo  hi how are you     grep -shoP          Just make sure you append a space to each one of your lines   Mine was a line by line search to spit out words

User · Answer

grep  For non-greedy match in grep you could use a negated character class  In other words  try to avoid wildcards   For example  to fetch all links to jpeg files from the page content  you d use   grep -o           jpg     To deal with multiple line  pipe the input through xargs first  For performance  use ripgrep

User · Answer

Sorry I am 9 years late  but this might work for the viewers in 2020   So suppose you have a line like  Hello my name is Jello   Now you want to find the words that start with  H  and end with  o   with any number of characters in between  And we don t want lines we just want words  So for that we can use the expression   grep  H     o  file   This will return all the words  The way this works is that  It will allow all the characters instead of space character in between  this way we can avoid multiple words in the same line   Now you can replace the space character with any other character you want  Suppose the initial line was  Hello-my-name-is-Jello   then you can get words using the expression   grep  H  -  o  file

[regex] How to do a non-greedy match in grep?

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