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

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how do i write a regular expression using grep to find lines that start with 'O' or 'o' AND contain 2 consecutive chracters

how do i write a regular expression using grep to find lines that start with 'O' or 'o' AND contain 2 consecutive 'c' characters. grep '^[Oo]c{2}' filename
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2answers
103 views

Using find -exec how to print name of file in front of each line?

Similar to, but beyond: find . -iname "somepatter*txt" -print -exec cat {} \; How might the file name from each file be printed in front of each line with the results from find?
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2answers
98 views

Remove specific (known) extension from filename if it's there

I'm not even sure whether grep is meant to be used for regex in one-line data. Googling led me to this lookahead expression that, along with grep, matches any .ext file and returns bare name: ...
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2answers
72 views

Using a shell variable with grep [closed]

I have a list of tokens in a text file and want to use grep to get the lines from a second text file that contain those tokens, but seem to be having trouble accessing the shell variable with grep: ...
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1answer
25 views

Regex quantifiers are not working well with locate

This output is rather self-explanatory: XXXXX@debianvirtualbox:~$ locate -r "^/var/lib/tomcat[0-9]/.*" -l 10 /var/lib/tomcat8/conf /var/lib/tomcat8/lib /var/lib/tomcat8/logs /var/lib/tomcat8/webapps ...
4
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3answers
151 views

egrep regular expression for times over five minutes

I have the following time formats in a text file `1` equals one second. `5|01` equals five minutes and one seconds. `13|01` equals thirteen minutes and one seconds. `21|12|01` equals 21 ...
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2answers
57 views

How to make + work in sed's regexps on FreeBSD?

Consider the following typescript: $ freebsd-version 10.0-RELEASE-p5 $ echo ' found' | sed -n '/[[:blank:]]\+/p' $ echo ' found' | grep '[[:blank:]]\+' found When I do this on Arch Linux with GNU ...
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3answers
231 views

grep regular expression solution (greedy not working)

I have the following text in the data.txt file :MENU1 0. public 1. admin 2. webmail :SYNTAX ! opt1, ... : :ERROR1 Error #1, blah... blah.. blah... Please do ... :ERROR2 Error #2 ... and I want ...
2
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2answers
91 views

Cleaning PHP exploits from infected files using sed

Recently my server has been a target for a series php exploit attacks and using ClamAV I was able to identify many infected files. The catch here is that there are legitimate files that are infected ...
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0answers
49 views

swap strings of text inside vim using regex

I am working with a file where I need to swap "string A" and "String B's" locations simultaneously with a regex inside the vim. Here is an example line of code: succ_1st=`grep 'resulted in successful ...
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1answer
78 views

Match everything after backslash and before space

I have strings similar to the following: *unknown*\*unknown* (8) hello\morning (3) I'm trying to match just morning or *unknown\*. So far I have tried: [^\\]+$ But that matches from backslash ...
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5answers
1k views

How to print file content only if the first line matches a certain pattern?

I am writing a script, I want to check if the first line of the file matches a certain pattern and if it does then print out the file. How can I achieve this? How do I check for pattern? Is there a ...
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votes
1answer
119 views

Regular expression: when every alternate character is a digit

I am trying to write a Linux command using egrep that validates lines whose even character is a number. I am doing it this way: egrep "^(.[0-9])*$" text.txt However, this fails for i) empty ...
0
votes
1answer
26 views

subtract dates from two files for same process

I have initiated 50 processes and in one file "say start_time", I have stored when process was started and in another file "say end_time", I have stored when process finished. files are like below - ...
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2answers
84 views

how to swap text inside files [duplicate]

Inside my file I need to swap places of all instances of : grep 'search string' and sed '/string of text/,/string of text/{//!d}' In VI I have tried a regex with no luck - it says something ...
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1answer
18 views

Is there a way to get all the NEWS.gz which is/was this year in /usr/share/doc/ of $PACKAGENAME.

If people go into /usr/share/doc/$PACKAGENAME (you can use any valid package name which you have installed on your system) you will see that the directory has various files in it, at the very least ...
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1answer
42 views

Regexp pattern - is it correct and what is its purpose? [closed]

Is this pattern correct? logPattern = ^NAME.log(-\d+)?$ What is the purpose of this?
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1answer
122 views

Including or in grep pattern

I want to grep a word wrap in single quote or double quote eg. "myWord" 'myWord' I am using grep -rn "\"\|\'myWord\'\|\"" this should allow "myWord" , 'myWord" , "myWord' and 'myWord' , but ...
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1answer
83 views

Why is vi (but not cat) showing ^[[31m[^[[m^[[31m" after I use sed and output to a file I then edit? [closed]

When I use cat Variables/user-extensions.js | sed -e 's/css/XXX/' on an input file of the form storedVars["css_body"] = "css=body"; storedVars["css_main"] = "css=main"; I see output such as ...
1
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1answer
181 views

Sed replace portions of lines not beginning with http://

I'm getting stuck with sed.. I'm trying to prefix links in an html file with a / when they don't start with http.. I'm aware this is possibly not the best way to go about this but I'm just after a ...
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3answers
239 views

parse credentials from PHP configuration file

I'd like to write bash script to parse data from a configuration file. I searched for this but without finding something I could modify to suit my needs. Joomla! config file: public $access = ...
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3answers
432 views

sed, convert single backslash to double backslash

I have a json string, which has a potpourri of doubly escaped/singly escaped newline chars. Json parser doesn't allow its string value to have single backslash escapes. I need to uniformly make all ...
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1answer
73 views

grep -E regex syntax changed?

A lot of documentation I've read says that the following command should match lines where x appears at least 3 times in a row but no more than 4 times in a row: grep -E {x}\{3,4} E.g. ...
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1answer
378 views

logstash regex match in if condition

In logstash filtering, I have multiple tags setup based upon different error conditions and all the tags has a prefix, something like "abc:" In the output, I want to send email based upon just ...
4
votes
1answer
373 views

Match pattern \\\" using grep

I have a json string inside json. This got encoded multiple times and I ended up with many escape backlashes: \\\". The much shortened string looks like, '[{"testId" : "12345", "message": "\\\"the ...
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3answers
106 views

Pulling out a certain value from a string via regex

I've see a bunch of examples, but I just can't seem to make this work. Can grep output only specified groupings that match? for example seems like it should work, but I get either errors or no output ...
2
votes
1answer
103 views

Double square parenthese inside grep pattern

grep "^[[:space:]]*clientPort[^[:alpha:]]" zoo.cfg This is a grep pattern to extract the line that contains the port number from the configuration file. 1) Normally in a regex, I use square ...
0
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2answers
155 views

Use multiple commands in sed to insert text after string with special characters

I am having a little trouble trying to do a search and replace using sed in a config file. I want to use multiple commands using the -e option to do the following. Step 1: find the first occurrence ...
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3answers
85 views

How to search multiple search patterns from a file with grep

If I search for multiple search strings in grep : usually just do: grep "search1\|search2" somefolder/*.txt but, what if I have 100 or more search strings? Can I say like this: grep ...
0
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2answers
48 views

Bash script to copy specific directories with pattern matching

How can I copy directories from one location to another location that matches a pattern. For example: source = /media/src/ destination = /media/dest/ The pattern is as /b/w{2}_/w{2}/b. i.e all ...
2
votes
1answer
73 views

Sed: replace text keeping digit occurrence

I have some text like: Blablabla <b>[intlink id="</b>2204<b>" type="page"] Blalala I want replace it for remove the </b> and <b>, keeping the id="number". So it should ...
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1answer
92 views

Need to capture part of file name into variable

I have bunch of CSV files named like so in a directory: s_m_u_supplemental_fields_account_9_4_2015_11_26_Error.csv s_m_u_supplemental_fields_account_9_4_2015_12_3_Error.csv ...
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2answers
58 views

Remove last comma within a pattern

If I have the following text within a file (somefile.txt): CREATE TABLE "table_name" ( "id" int(11) unsigned NOT NULL, "some_field" varchar(10), ); CREATE TABLE "another_table" ( "id" ...
1
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1answer
52 views

Remove word after match

Consider the following line of text (taken from a MySQL insert): "description" varchar(255) COLLATE utf8_unicode_ci NOT NULL DEFAULT '', I want to return "description" varchar(255) NOT NULL ...
2
votes
1answer
61 views

Meaning of this character class in perl?

I am new with PERL(though I have good background in reg-ex), I was going through one perl script and it has one characters class $alwayssep = "[\\?!()\";/\\|‘]"; Can anyone explain to me what is ...
2
votes
4answers
330 views

extract url between 2 strings in a file

I have a file in which each line is like this "372"^""^"2015-09-03 06:59:44.475"^"NEW"^"N/A"^""^0^"105592"^"https://example-url.com"^"example-domain < MEN'S ULTRA < UltraSeriesViewAll ...
4
votes
2answers
340 views

How to change all strings in python file from snake_case to camelCase in sed

I've tried some sed patterns like this from commandlinefu sed -r "s/('[a-z]+)_([a-z])([a-z]+)/\1\U\2\L\3/" But somehow it's not working. For one thing they forgot the digits, which I can fix, but ...
6
votes
4answers
828 views

How to add a header and/or footer to a sed or awk stream?

I have a bunch of output going through sed and awk. How can I prefix the output with START and suffix the answer with END? For example, if I have All this code on all these lines and all these ...
1
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4answers
85 views

Match regular expression between delimiters

I have a file with several different lines. I'm looking for lines that contain(more or less) pattern like this: \[.*<.*>.*\] In other words, I want the lines that have <something> ...
0
votes
1answer
111 views

How to grep the following lines from a file?

I have a file which has the names of many files in a directory in the following format: A20150824.0950-0955_jambala_CcnActiveSessionCounterJob A20150824.0945-0950_jambala_CcnActiveSessionCounterJob ...
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votes
1answer
42 views

sed: regular expression,how to substitute?

I have those line on a text file 36) SIGCANCEL 37) SIGLOST 38) SIGXRES 39) SIGJVM1 40) SIGJVM2 41) SIGRTMIN 42) SIGRTMIN+1 43) SIGRTMIN+2 44) SIGRTMIN+3 45) SIGRTMAX-3 46) SIGRTMAX-2 47) SIGRTMAX-1 ...
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2answers
85 views

Awk & regular expression to process pgn chess games file

Below an extract of the sample.pgn file [Event "rated blitz match"] [Site "Internet Chess Server"] [Date "2015.08.20"] [Round "?"] [White "Villain"] [Black "Hero"] [Result "0-1"] [WhiteElo "1643"] ...
2
votes
1answer
91 views

How to combine POSIX character classes of a regex?

I need to combine different character classes in a regular expresion used by sed. I need to match [:word:] and the minus symbol -. How does that look like? All my attempts failed at trying or ...
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0answers
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what is the correct regexp for mysql filter in fail2ban?

I use the default filter file /etc/fail2ban/filter.d/mysqld-auth.conf for fail2ban service. But there are some errors in file /var/log/fail2ban.log as: Found a match for '150815 10:42:54 [Warning] ...
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1answer
142 views

How to use sed to replace keys in a file using a regex?

I would like to modify a file to replace keys, suppose these keys are in the file as: 42NM 52NM 23NO XNNM I would like to replace anything with NM, with the word "Okay". 1 #!bin/bash/ 2 3 if [ ...
4
votes
1answer
261 views

POSIX behavior of sed's ^ and $ regex anchors with multiline pattern spaces

What is the POSIX behavior of the sed ^ and $ anchors when used at the beginning and end of a regex if the pattern space contains embedded newlines, like after you use the N command? Should they ...
0
votes
2answers
250 views

AWK, SED or GREP for extracting data from HTML file

Can anyone tell me which is best to use to extract the following data from a html file which was received with curl . <script>document.getElementById("test-summary").innerHTML = ...
5
votes
3answers
62 views

Censor text with regex

I'm currently running this command to censor an indented to-do list. sed -e 's/\(\s\+- \)\(.*\)/\1XXX/g' It's great except that I'd like the number of Xs to match the number of matched characters. ...
0
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2answers
483 views

What's wrong with this grep?

> output2.txt cd # some directory i'm trying to search find views/shared -type f -name "*.js" -print0 | while IFS= read -r -d $'\0' line; do echo -n "${line%.js}" | tee -a ...
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3answers
58 views

Remove words (letters followed by space) from a specific column

I have a file and the format is as follows: cat dog AHF123432 | 123432 | dhfshfjdh lion AFG23412 |23412 | dfshjhfjdhj I need to remove those words from first column which contains only alphabets ...