Unfortunately it doesn't work anymore when I try to use it with grep. I try to do the following thing: cat foo.log grep -E '(?regex after this pattern. Also the -E param worked because the regex. worked fine. A look into the config. One grep version I tried lately is the one bundled with Cygwin. I don't like it because the regular expression syntax it uses is rudimentary. It has a '-P' flag for Perl-like regex, but the manual states that it is experimental, and indeed it worked poorly when I tried it.
The right after can be a test of a large file named AT5G60410.gff:
I feel getting some problems extracting specific ranges from this using grep. I desired to draw out all outlines that are usually of type 'gene' or type 'exon', selected in the third column. I was suprised when this do not work:
No results are returned. Where have I eliminated incorrect?
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5 Answers
You require to escape the
Jeff FosterJeff Foster
. The sticking with should perform the work.35.7k1010 gold badges7474 gold badges100100 bronze badges
By default, grep snacks the usual special people as normal people unless they are usually escaped. So you could make use of the following:
However, you can alter its setting by using the following types to do what you are anticipating:
a'la'l![Regex Regex](/uploads/1/2/5/7/125714698/990014872.jpg)
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This is definitely a various way of grepping for a few options:
the
Nathan FellmanNathan Fellman-elizabeth
switch specifies different styles to match up.64k8282 yellow metal badges226226 magic badges293293 bronze badges
ennuikillerennuikiller38.4k1313 money badges102102 magic badges131131 bronze badges
I found this question while googling for a particular issue I has been having involving a piped order to a
grep
order that utilized the alternation user in a regex, so I believed that I would contribute my even more specialized reply.The error I encountered converted out to become with the earlier pipe owner (i.e.
) and not really the alternation user (i.age.
similar to tube operator) in the grep regex at all. The answer for me was to correctly escape and estimate as essential special shell characters such as amp; before supposing the issue had been with my grep regex that included the alternation operator.For instance, the control I executed on my local machine had been:
This order resulted in the following mistake:
This mistake was adjusted by modifying my control to:
By getting away the
entpnerdentpnerdamp;
personality with dual quotations I was capable to resolve my concern. The reply had nothing at all to perform with the alternation operation at all.5,42522 gold badges2424 magic badges4747 bronze badges
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I have always been attempting to make use of grep with a regex to discover ranges in a file that suit 1 of 2 possible strings. Right here is my grep:
The above grep results no results. Nevertheless if I execute either:
or
I perform match particular ranges. Why is usually my OR regex not really matching? Thanks in advance for the help!
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2 Answers
With regular regex, the character types
(
,
and)
want to become escaped. So you should useYou put on't require the escapes when you use theexpanded regex(
rozcietrzewiaczrozcietrzewiacz-Elizabeth
)option. Findman grep
, area 'Basic vs Extended Regular Expressions
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If you need to use multiple limbs (the
asor
), after that to end up being more compatible, it's much better to explicit state you would like to make use of 'contemporary RE' aka. ERE.To perform so, make use ofgrep -E:
To understand even more about RE, ERE and the entire 'modern' ER tale notice
man 7 regex
.On the other hand you can make use of
egrep
rather ofgrep
, but as you can study fromguy grep
:egrep will be the same as grep -E. fgrep is usually the exact same as grep -N
(.)
Direct invocation as eitheregreporfgrepis definitelydeprecated
Michał ŠrajerMichał Šrajer