Regular expressions are a means of matching a pattern of characters within a string.

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409 views

Shell script to add or replace block of text?

I'm looking for a shell script (Bash) that adds or replaces copyright text at the beginning of the file (for .c and .h files). It should search and add or replace the copyright text block for all the ...
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1answer
61 views

combining grep ignore and matches

I would like to grep a file to find all instances of the text fn1 that don't have the word call in front of it and print out four lines before and after the matches (even if the surrounding lines have ...
3
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2answers
168 views

Sed: modify every non-first word repetition for every word in text

Can you help me to do something like that using sed? qq ab xyz ab qq aa ab Becomes: qq ab xyz +ab+ +qq+ aa +ab+
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2answers
45 views

Why doesn't my regex work in bash “if”? [duplicate]

Here is my code: if [ -f /Applications/xml[0-9].pl ] I also tried with -f =~ and double brackets but none seem to work. I first though that the regex might be faulty but I tried this. echo h1 | ...
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2answers
133 views

Bash regex string manipulation bug

I have an issue with bash and its regex match ability that I for now think is a bug in bash but could also be me having missed something obvious. I hope it is the latter. I have made this function in ...
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2answers
58 views

Regex long list of numbers

What is the command in Linux to find the regular expression e for every number from 37 to 200 included in a list with such numbers?
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2answers
136 views

Coloring tail output with perl

tail -f logfile.log | perl -pe 's/.*foo*/\e[1;41m$&\e[0m/g' will color all the lines containing the pattern "foo" in the logfile.log file. How can I make use of this in order to highlight ...
2
votes
2answers
149 views

regex - Searching for only character pairs

I have the following data from which I mean to extract only those lines which contain "bb" only. Not "b" or "bbb" or anything else just "bb". abb abbb aabbcc aabab abbbbc Now when I use the ...
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1answer
60 views

No output from grep -P 'com\K\w+'

I have a source file saved off the internet which has various links I want to pull data from. For example https://blahblah.com/uniquetext I'm using grep -oP 'com\K\w+' source.txt > list.txt ...
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2answers
904 views

grep pattern exacly matching from file and search only in first column

I have a bigfile like this: denovo1 xxx yyyy oggugu ddddd denovo11 ggg hhhh bbbb gggg denovo22 hhhh yyyy kkkk iiii denovo2 yyyyy rrrr fffff jjjj denovo33 hhh yyy eeeee fffff then my pattern file ...
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2answers
51 views

How to make my regular expression accept zeroes in the input?

I wrote a regex that accepts numbers between 0 and 999,999,999,999.99. Commas are optional, but, still should accept value not higher than 999999999999.99. I wrote one, but, there are two flaws in it. ...
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5answers
1k views

Remove backslashes from a text file

I have Input: NISHA =\455 Output: NISHA = 455 I want to remove \ from output. I tried to use command sed "s/[\]//g" P but it is not working and it flags an error: character found ...
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votes
3answers
98 views

Parsing Log Files with sed -e. Need to count unique class names

I have a file, let's call it filename.log, in it I have something like this (2014-11-18 14:09:21,766), , xxxxxx.local, EventSystem, DEBUG FtpsFile delay secs is 5 [pool-3-thread-7] (2014-11-18 ...
1
vote
4answers
416 views

SED command not replacing (working regex)

I'm trying to replace in one of my projects all mysql to mysqli, with their parameters. To do so, I'm searching for all files with mysql in my folder recursively and replacing it with mysqli. Ex: ...
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0answers
79 views

how to exclude range of numbers using regular expression

I'm trying to write a regular expression in order to cover all numbers starting with 1809 and excluding some ranges: Ranges needed to be excluded Starting with 1809 and followed by: ...
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3answers
167 views

Why does my grep expression need to use $'string' to match tab characters?

If you take this code: echo -e '\t\t\tString' | grep '^[\t]*String' the result is blank because it doesn't match, yet this: echo -e '\t\t\tString' | grep $'^[\t]*String' works. I swear that I ...
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1answer
32 views

regexp in find to locate only

I have csv file (products.csv) with product numbers $ cat products.csv | head -3 2.20 2.21 2.22 in another directory I have thousands of product images in subdirectories. I need to locate product ...
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0answers
36 views

grc: Highlight capture groups only?

Recently I came across grc and I find it really simple. However, I would like to highlight some chunks of regex-matched text. For example, svn status properties conflict highlight I hoped to work: ...
2
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4answers
303 views

remove leading string in bash

I try getting this sed command to work. I have a string like rev00000010 and I only want the last number, 10 in that case. I have tried this: TEST='rev00000010' echo "$TEST" | sed ...
0
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3answers
195 views

Simple way to extract value from HTML

I have a very simple html file with a value inside. Value is 57 in this case. <eta version="1.0"><value uri="/user/var/48/10391/0/0/12528" strValue="57" unit="%" decPlaces="0" ...
1
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1answer
38 views

Search and remove with regular expression

How do you use regular expression in bash to search any given string and remove occurrence of particular word? This is the expression I've come up with ^([A-Za-z-]+)(-).*(el6.*)$ What I would like ...
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2answers
97 views

How can I use sed to remove the first paragraph of the file?

So the paragraph is defined by having a empty line at the end. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nunc et nisi tristique, facilisis orci nec, pellentesque tortor. ...
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1answer
70 views

perl rename: Prepending something to a set of file names across subdirectories

Although perl's rename tool has become an invaluable companion for my daily work, there are still some quirks that make work more difficult - especially when files are not in current work directory. ...
4
votes
3answers
283 views

Use sed to delete all but a certain pattern

How do I get just the link part in the http-source of a link? I have <a href="http://unix.stackexchange.com/users/20661/">Unix &amp; Linux and would like to get just ...
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1answer
40 views

SMTP log anonymize script

I have a SMTP log with records in the format below: 6,222.3.4.5,3040,100.2.3.4,25,UNKNOWN,0,1,……,9337bc-929a-34c0-29a8-b3a89c834b29 ,protocol,SMTP ,745663746,STATUS-COMPLETE ,VALID ...
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5answers
133 views

Regular Expression for Mixed cased words

I want a regular expression that will help me identify if a certain pattern is present as a mixed case in a sentence or not. Say: Fox juMPed the rock Now, I want to find that if the pattern ...
0
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1answer
364 views

How to escape unbalanced brackets or slash in sed?

I'm trying to use sed, but my pattern contains [] brackets and slashes (/). I've tried quotes, but it doesn't help. How do I escape it? Examples: $ sed -i'.bak' "s/^includes[] =/;includes[] ...
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5answers
374 views

how to use regex in alias?

I want to create the alias for the command "ssh user@10.32.44.225" as 10.32.44.225 alias [0-9][0-9][0-9].[0-9][0-9][0-9].[0-9][0-9][0-9].[0-9][0-9][0-9]="ssh user@$0" I have created it, but it is ...
0
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0answers
19 views

To visualise look-behind in this Regex

I am using Regexr to visualise my regexes now. I need look-behind but Javascript does not support it, example code here. The project code base seems to be dependent Javascript (NodeJS) in Github. I ...
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2answers
486 views

In VIM, replace path with slashes without using escape slashes

In vim I want to substitute a long path /a/b/f/g/d/g with another /s/g/w/d/g/r in a text file. Usually I use \/ but there are too many slashes here. Is there an easier way?
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1answer
81 views

How to nest global matches with sed?

If I do: sed 's/match/replace/g' I know that sed will substitute replace for every occurrence of match on a line. But what if...? echo "match <please dont match this?>" | sed ...
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0answers
61 views

Need .htaccess Rewrite Rule To Remove Trailing <br%20/>

I have links that for some reason have a trailing <br%20/> and I don't know where they are coming from to try and fix them. So I need a general rewrite rule to remove them so the links won't ...
2
votes
2answers
228 views

How can I remove lines matching foo but not matching bar?

Assume I want to remove the 2nd and 3rd, but not the 4th line in the following file (those which match foo but do not match bar), can I easily do this with e.g. sed? text foo some more text even more ...
3
votes
4answers
329 views

Decreasing a number with sed

I extracted the metadata of a PDF in a .txt file using pdftk, and now I am trying to decrease the BookmarkPageNumber value for each bookmark by an integer. The .txt has these lines: BookmarkBegin ...
1
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3answers
607 views

Remove patterns from string using bash

I'm trying to remove some patterns from a file input string (parsing file line by line). Here is a sample string: 1: (10/17 12:49:31.175) - CONSTANT ID1 - CONSTANT ID2: RAW DATA OUT > ...
1
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1answer
67 views

Regex for contains at least one instance of STRINGA and no instances of STRINGB

What regex will match: contains at least one instance of "1221", and no instances of "7474" i.e. matches "7777 1221 4543" but does not match "7777 1221 7474 4543" I suspect I have to use negative ...
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4answers
496 views

Regular expression using \\ vs using \

Why does grep e\\.g\\. <<< "this is an e.g. wow" and grep e\.g\. <<< "this is an e.g. wow" do the same thing? If I add a third slash, it also has the same result. BUT, once I ...
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2answers
76 views

What does this regex mean? <!--.*?-->

What does this regex do? <!--.*?-->
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1answer
327 views

Regular expression to mask credit card digits in a file

What is the most simplest way to mask all numbers but the last 4 digits of a credit card number in a file using sed. Using egrep with the following regular expression we can find numbers of Visa, ...
0
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0answers
88 views

Find & replace image URLs in one file from another file

I am trying to replace all the image source URLs in an HTML file from a list of URLs in a text file. File1.html <td class="MetadataRes" width="380px" colspan="2" style="border-top: 1px #336699 ...
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3answers
597 views

“bad flag in substitute command: '{” while replacing a string with sed from one file to another file

I am trying to replace strings found in File1 with strings in File2 File1 <IMG SRC="/Repository/GetImage.dll?baseHref=Orange/2011/03/27&amp;EntityID=Ad12911&amp;imgExtension=" /> ...
2
votes
4answers
103 views

replace several comma out side one or more sets of curly braces and exception that in one or more sets of curly braces

In the text file I have multi records. Every record has multi column with comma separated, some column have one sets of curly brace and other have more than one curly brace. I need: If a comma is ...
0
votes
2answers
106 views

Regex to grep filler followed by signed float

I want to extract the last column from lines that look like: 880.952 NAV_Y uSimMarine -146.17516 The number isn't always negative, and isn't a fixed length (i.e. doesn't ...
2
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2answers
46 views

Match from current line until a line that doesn't match a pattern

I really tried searching but could not find anything (it's hard to know what exactly to search for). I know how to do this with sed: print from current line until the line that matches SOMETHING: ...
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1answer
211 views

Regex works in shell but not through Perl script

I'm having trouble executing a Perl script through the Unix shell using Perl's system command. I've had more complex regex commands I had to adjust accordingly to convert from Unix to Perl, and ...
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2answers
57 views

To match only innermost environment by Regex

I want to match the innermost environment of begin{question} and its corresponding end{question}. Example data \section{Takayasu arteritis} \begin{question} {You get a patient. What do you notice ...
2
votes
1answer
149 views

To write this Pseudocode with Regex

I am doing a Makefile which I run regularly by Crontab every day at 0230 crontab -e; 30 2 * * * /bin/thePseudocode Python-like Pseudocode directories = ["Cardiology", "Rheumatology", "Surgery"] ...
0
votes
3answers
111 views

Bash Combine Replacement and Sub String Extraction in One Step

For a string in this format: ./my-site.sub.domain.com I would like to remove the .,-, and /, and trim the remainder to 16 characters: mysitesubdomainc I've done this ...
4
votes
4answers
171 views

Replace using vim - Replace a pattern […] by a string

I have a file containing lines in below e.g. format - [foo@host.com, bar@host.com], Payment processed - 23499, params = {'invoice':3243} I only want the account numbers i.e. 23499. It's a number. ...
2
votes
2answers
127 views

What is the regex to validate Linux users?

When adding a new user, how is the string validated? I suppose there is a regular expression. What is that regular expression?