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

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grep with regular expression

I want to match all the lines that are of the below pattern in a file using grep. Abc::xyz() [18-Feb-15 12:09:16] I came up with below regex with grep , but it is not returning match. Please help ...
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4answers
282 views

How do I extract parts of a string to variables?

I have a line from some file like this: attempting to create a 512^3 level (with Dirichlet BC) using a 16^3 grid of 32^3 boxes and 800 tasks... I want to extract the 512^3, 16^3, 32^3 and 800 four ...
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1answer
26 views

sed exception handling of escaped characters

I want to delete anything that follows a % to the end of the line. Using cat /tmp/foo.txt | sed 's/%.*$//' works great with one exception: I want to ignore any escaped percent signs \%. So with ...
2
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1answer
41 views

Using fixed strings in regular expressions?

I am writing a bash script which accepts a list of CSV files as arguments and outputs e-mail addresses only found in the first file. To accomplish this, for each record in the first CSV file I look ...
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7answers
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How can I “grep” patterns across multiple lines?

It seems I am misusing grep/egrep. I was trying to search for strings in multiple line and could not find a match while I know that what I'm looking for should match. Originally I thought that my ...
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1answer
77 views

Sed command that would ignore any commented match

I'm trying to create a sed command using regex in order to substitute something in a text file only if it is not commented but I'm running into some troubles due to my almost non-existent knowledge of ...
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2answers
34 views

Perl non-greedy regex matching more than it should

I have the following text from which I need to remove some wdiff output. text='Иса Мәсіхтің елшісі Петірден [-(-] осы күнәкар дүниеде [-)-] жат жерлік болып, Понти, Ғалатия, [-Қападоқия, Азия және ...
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1answer
44 views

Bash detect ascii art [closed]

For bash script, is there a easy way to detect if a text contains ascii art? An example of ascii art:
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0answers
58 views

Bash regular expression comparison fail for hex byte \x01

Bash regular expression fails to compare correctly for $'\x01' when End-Of-String char $ is used. All other byte values (seem to) compare correctly. Using GNU bash 4.1.5(1). Is this a bug, or is ...
0
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1answer
33 views

What is the email matching regex in basic regex for grep?

I created a text file and put some email addresses in it. Then I used grep to find them. Indeed it worked: # pattern="^[a-zA-Z0-9]+@[a-zA-Z0-9]+\.[a-z]{2,}" # grep -E $pattern regexfile but only as ...
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Regex: match word in line 1-3 times

My question is about regular expressions and searching for text. I need to search for all lines in text that contain one ceratin word, let's say "cat", one, two or three times.
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1answer
33 views

Vim: Count all occurrences (including multiple on the same line) of char or word

I try to count all occurrences of a char or word in a file with Vim. This means multiple occurrences of the same word in the same line should be taken into account as well. This has been discussed in ...
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3answers
670 views

Strange behaviour of “ls -a | grep ^\.”

I wanted to list the content of a pwd and display only file starting with dot. I tried ls -a | grep ^\. but I cannot figure out why the output contains also the files which do not start with dot. For ...
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1answer
38 views

Find only in directories n levels deep

I use this command to find and run all istances of wp-cron.php I have for each site I have: find /var/www/ -name 'wp-cron.php' -exec php -q "{}" \; Since my websites tree is: ...
0
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1answer
22 views

Interactive less search with wildcards [duplicate]

I'm using less to view a large file and I want to search for a pattern with wildcards — e.g., " x 1??" where ? is any character. Does less support that, and if so how would I do that ...
5
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5answers
356 views

How to replace a word with new line

I have a text file with following data and each row ends with |END|. T|somthing|something|END|T|something2|something2|END| I am tryig to replace |END| with \n new line with sed. sed ...
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2answers
32 views

Vim: Substitute based on another match in the line

I have rather large files in which I need to substitute NX for N1 but only if the line already contains NX as a pattern. So far I do it manually by first searching for occurrences of NX with: /NX ...
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2answers
432 views

Regular expressions with ExpectJ

I've been used the ExpectJ Java library to automate some jobs on a Linux server, however now I need to automate a job that sends a different text response for each execution. Here is the output: Last ...
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3answers
129 views

How to perform grep onto the output of ldd properly ?

# ldd /usr/bin/ffmpeg linux-vdso.so.1 => (0x00007ffffc1fe000) libavfilter.so.0 => not found libpostproc.so.51 => not found libswscale.so.0 => not found ...
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5answers
286 views

How to grep the n-th substring between given delimiters?

Let's say we have a string and its delimiter is ?: Leslie Cheung April 1 ? Elvis August 16 ? Leonard Nimoy February 27 I know how to grep the first substring between delimiters: echo $above_string ...
1
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1answer
48 views

Pattern matching and removal of that pattern using sed

I have 2 files with the following names: File 1: RvA_X-IRB-bil-CA101-0+010000-20150327212332-055582-P File 2: RvA_X-IRB-bil-CA101-1+020000-20150327212332-055582-P I am using this command to match ...
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3answers
41 views

grep log lines of a specific id request

So, I have the following log sample: 2015-03-30 10:19:44,200 DEBUG [Default : 1] [Application:ABC BIW: IDA:6d87de8e-1276-4496-b49d-dd4cd375cbe4 Info:P23 Code:ABCD] A log message 1 2015-03-30 ...
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2answers
47 views

Parsing C Style Multiline Comment

I want to filter non-commented javascript with sed and output the line number Here is the example: /*! * jQuery UI 1.8.17 * * Copyright 2011, AUTHORS.txt (http://jqueryui.com/about) * Dual ...
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Shell test to find a pattern in a string

I just wanted to ask whether there is any command which would work on common shells (bash, dash, kornshell)? It is supposed to check if the line variable contains any part of the path. if [[ $line =~ ...
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85 views

regular expression to extract information in shell script

I would to grep certain parts of some shell command output in the shell script: $ uname -r >> 3.14.37-1-lts Where I just need the 3.14.37. And also for the shell script variable VERSION that ...
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4answers
39 views

AWK print regex pattern

I am trying to print a regex pattern for the following piece of mail log. In particular I am trying to get the ID between the square brackets (see the second line for reference). Mar 29 03:48:13 ...
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1answer
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Is it possible to get static backreference with grep?

I try to match a a group twice in multiline. grep -Pz 'Source: (?<group>.*/).*\n.*\n.*\n.*\k<group>|$' it work except one major problem - it doesn't, \k<group> search for .*/ and ...
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1answer
31 views

Bourne shell: ignoring certain kinds of stdin

I have a program that is currently working, but I need to modify it to ignore some stdin that is not fitting for its correct function. Right now, to run the program: printf "1\n3\n5\n" | sh prog The ...
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6answers
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How can I use sed to replace a multi-line string?

I've noticed that, if I add \n to a patter for a substitute using sed, it does not match. Example: $ cat > alpha.txt This is a test Please do not be alarmed $ sed -i'.original' 's/a test\nPlease ...
0
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1answer
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Using regular expressions to search a word list. Finding 2 letter words instead of 3. Why?

I am studying regular expressions and I am stumped. Here is my process so far.... I downloaded this file. wget http://www.mieliestronk.com/corncob_lowercase.txt mv corncob_lowercase.txt words.txt ...
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How to diff files ignoring comments (lines starting with #)?

I've two configuration files, the original from the package manager and a customized one modified by myself. I've added some comments to describe behavior. How can I run diff on the configuration ...
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1answer
51 views

How to search mail logs effectively with `RegEx`

I was looking for some advice and examples on searching mail log effectively Suppose situation is like this -------- Forwarded Message -------- Subject: Fwd: Re: Notice of Allowance Date: Fri, 13 ...
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2answers
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Regular expression for excluding data within a certain range

I want to remove all the IP addresses which are of the format 10.20.30.* and whose last 3 digits fall in the range 0 to 200 and move all the remaining IPs to a new file. I've put the IP list to be ...
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2answers
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Negative lookbehind/ahead assertions in Linux less pager (or vim)

I want to find all instances of "index" not followed by .php in a log using less. /index(?!\.php) does not work. Is this possible? What is the regex for less and vim (do they differ?). Is this not ...
2
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3answers
50 views

Regular expression that ignores certain characters

I need to find a regular expression, that ignores certain characters for usage in the bib2bib tool. For example: I need to find any occurence of the word "muller". But also a string like ''Hello, ...
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2answers
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Pages don't get blocked with Squid over HTTPS

I have set up Squid to block pages on my own system (i.e not on a network), and I'm trying to get SSL to work with page blocking. To this end, I've set up ssl-bump and installed the certificate to my ...
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2answers
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How to use variables in substitution with vim regular expressions

I have a big file that contains among others serveral lines of the following form: USet07-1 USet07-2 USet08-1 USet08-2 . . . USet22-2 . . . I want to remove the hyphen/dash - from these strings in ...
0
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1answer
38 views

effect of [0-9]* in a regular expression

What is the function of [0-9]* in the following statement, which will write all lines that start with an even number, followed by a space, to the file even: sed -n 's/^[0-9]*[02468] /&/w even' ...
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1answer
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Problem with sed substition in multi-word regex

Take this simple example: echo "20150310 21:12:01.846338::: <?xml version="1.0"?><Haystack><Event " \ | sed 's/^\(.\{24\}\)::: \(<?xml.*><Haystack\|Foo\)>\(.*\)/\2 ...
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1answer
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Emacs: query-replace prepend text to the found string

The scenario is that I am trying to append a new class to all the style declrations in my css file. So .oldclass{ float : left; } should change to .newclass .oldclass{ float : left; } The ...
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0answers
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SED: print entire paragraph for specific pattern while loop

I find partial answer about my problem on this question but i still have trouble. I need to use a variable as a pattern for the sed command in a loop sed -e '/./{H;$!d;}' -e 'x;/'$var'/!d;' The ...
5
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1answer
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file(1) and magic(5) : prioritizing a result

My question follows that one: file(1) and magic(5) : describing other formats . I want to describe a FASTA sequence ( http://en.wikipedia.org/wiki/FASTA_format) It could be a DNA sequence (with only ...
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To remove \n but not \n\n

Data 23. Lorem A) he B) ha C) hu c 2. Ipsun yes right to write something here? A) Ok B) No C) yes b 292. Ipsun A) Apex B) hello b 289. He A) hu B) Ha C) He The right answer is: 1) Ab 2) Abc 3) ...
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1answer
49 views

Searching file for string surrounded by two other known string?

Question title may be kinda vague, but heres what im attempting to do. I have a html file locally on my server which is changing fairly regularly. It has multiple occurrences of: <p>Jumble of ...
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Find and change certain LaTeX coding in vim, using regular expressions?

How can I change the following LaTeX coding: \cite{1,3-7,9} to \cite{1,3,4,5,6,7,9} in vim? I would prefer to use regular expressions.
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1answer
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how to modify matches to a regular expression with sed or another tool?

I need to manipulate text that's in a file. I need to append a right parenthesis – ) – after every number that's preceded by a comma – , – e.g., ,4   ➜ ,4) ,15 ➜ ,15) I am struggling to find the ...
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2answers
28 views

How to search parenthesis by ack

I want to search for a parentheis ( using ack, but neither using ( nor \( worked. The first one ("(") is recognized as a multiple line command. The second one ("\(") is treated as an invalid regular ...
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0answers
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use php variables for awk regex commands [duplicate]

trying to implement autosuggest using php. autosuggest list generated using awk $input= $_GET["term"]; $suggest=array(); exec('awk \'BEGIN{FS=","}/.$input./{print $2,"-cost-",$1}\' ...
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What is SELinux's regex type?

I'm trying to locate all files on my system matching an SELinux file context (fcontext). These contexts are specified using some regex, and I'd like to use find -regex ... to the same effect. However, ...
0
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1answer
31 views

Printing out range of a pattern with awk

Im trying to print out a section of a txt file using awk. Basically I want to print out the paragraph in the a txt file that begins with certain words all up to a blank line.Here's what I have so far: ...