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

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5
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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
485 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 ...
1
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3answers
59 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 ...
3
votes
1answer
79 views

What is the effect of the underscore in [A-Z] [_a-zA-Z0-9]*?

In regards to regular-expressions what is the effect of the underscore in [A-Z][_a-zA-Z0-9]*
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1answer
87 views

Bash script with “execute” command and strange regexp

So I was looking through Paul Irish's dotfiles and found reference to this bash script: #!/bin/bash cd "$(dirname "$BASH_SOURCE")" \ && source 'utils.sh' declare -a FILES_TO_SYMLINK=( ...
1
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1answer
38 views

How to express “There is a specified symbol in the following unknown numbers of characters” in regex(vim)?

I have many python code examples in my markdown files, which should be prepended with >>> symbols. So I write a vim function to do this job: function AddShellPrompt() range let lnum = ...
2
votes
1answer
282 views

How to use regex inside exec with find?

Is it possible to use regular expressions based on the result (file name) inside the exec argument with find? I want to be able to "exec" based on parts of the argument, like: find . -name pattern ...
1
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1answer
59 views

grep also returning non matching lines

I'm trying to grep the output of strings and only find lines that start with a certain number of = chars. I tried strings data.txt | grep ^=* Sample output: 1~{, WX2 };K,< ========== ...
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2answers
272 views

Grep and ignoring leading whitespace

I've been working on a bash script to search for names of defines, and then grab the hex values for them and put them in the list. Once I have the list of names I'll attempt to search for "#define ...
4
votes
6answers
402 views

Grep the text which matches with a pattern

I was looking for a command which will print the selected portion of a line which matches the conditions. Eg, my text line is like this: p1=X||p2=Y||p3=X||p4=X||p5=X||p6=Y||p7=X I want to print ...
0
votes
1answer
63 views

sed - find string made of 4 numbers with a preceding character and append character

I'm trying to build a sed command that will allow me to search and replace some values in a large csv file. I have this column which contains years, like 2005 - 2006 2001 - 2003 and so on, but I also ...
1
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1answer
86 views

LFTP exclude file extensions

I am trying to mirror directories with lftp but I don't want to download filetypes that are notoriously large like .mp4 and .swf. But I am having trouble with the regex - and seeming like the ...
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1answer
41 views

Locate --regex with negative lookahead

Problem I tried to implement a negative lookahead when searching a file with locate like this: locate --regex "apple(?!t)" However I'm getting the following error, because there seems to be some ...
2
votes
4answers
332 views

Replace regex match with string containing match

I have a file with text as Afghanistan=+93 Albania=+355 Algeria=+213 American Samoa=+1 Andorra=+376 Angola=+244 It has all the country list and its dialing code. I want to replace: ...
2
votes
5answers
327 views

Duplicate lines and make them unique?

I have the following structure of text lines: 3923 001 L05 LV,L05 RM 3923 002 L12 RA,L12 LA 3923 003 I06 ALL 3923 004 G04 RV,Z09 ALL but i would need this: 3923 001 L05 LV 3923 001 ...
1
vote
2answers
239 views

how to replace a sed/perl expression (change and print only matched line) with a python expression?

I have asked this question to learn how perl could replace sed. Now I want to know how the following commands (which do the same thing) would look like for python: sed -n ...
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2answers
111 views

how to replace a sed expression (change and print only matched line) with a perl expression?

I am trying to move to perl (from sed). But how can I replace this sed expression with perl in a similarly short way? sed -n '/patternmatch/s%stuff%changed%p' file I need to search for a pattern, ...
0
votes
2answers
77 views

grep for lines/files that contain exactly X chars

Here's the output of a grep command I ran: [user@localhost] : ~/Documents/challenge $ grep -i -e ".\{32\}" fileA fileB fileA:W0mMhUcRRnG8dcghE4qvk3JA9lGt8nDl fileB:observacion = new Observacion(); ...
0
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1answer
47 views

emacs dired regexp mark files beginning with

In Emacs Dired mode, I'd like to mark directories and files whose names begin with Addr but not files that contain Addr inside the name. I'm using RE-Builder to test my regular expressions and am ...
0
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2answers
66 views

Delete folders using regex

I would like to delete folders with specified regex, but I could not build a good regex. I have: /root /my-picture-2015 /my-picture-2015-1 /my-picture-2015-2 /my-picture-2015-1 ...
2
votes
5answers
224 views

Testing if files start with certain letters and contain no special character except for period at end next to file extension in a shell script

I have a shell script that runs a for loop to execute a command on multiple text files in a folder. I want to test if these files' names start with a specific set of letters (NA for instance), and ...
2
votes
1answer
46 views

How do I match the beginning of a line in a manpage?

When I do man zshbuiltins I typically want to search for a command. Suppose I'm looking for info on the alias command. I get a chunk of text like: : [ arg ... ] This command does ...
4
votes
3answers
149 views

Undo letterspacing with sed

I have a source text file containing text where some words are l e t t e r s p a c e d like the word "letterspaced" in this question (i.e., there is a space character between the letters of the word. ...
2
votes
1answer
64 views

Move up every other line to end of line containing character

I have run two xpath queries piped together to retrieve certain information. However the results came out formatted on separate lines while I want them to be on the same line. For example the lines ...
2
votes
1answer
245 views

regex usage in exim filtering

I'm trying to create an exim filter to block spam messages containing " 85% OFF" in the subject line. That's a blank space, then any two digits, then the percent sign, a blank space and the ...
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vote
4answers
246 views

Delete everything before “/” on every line

I am trying to delete certain text that appears before / on every line. I have something like: testing.db.com/7fad416d-f2b3-4259-b98d-2449957a3123 ...
0
votes
1answer
33 views

Wrap all lines with character sequence in vim

So basically I copy/pasted some code, and I need to prepend and append some more code to each line. Each line is a function call, and is getting added to a switch statement as it's own case. Right ...
0
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2answers
90 views

get values which only occur once in a vector

There is a vector of numbers I have which are in ascending order (it is called t8_) 2 7 8 9 11 15 34 91 91 92 94 The problem is that some numbers happen two times. I don't want to remove them, but ...
7
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3answers
665 views

How to replace text between two markers in a file with a section of text from another file?

Say I had a block of text in the ~/.bashrc: #~/.bashrc # ...some commands... # aliases alias suicide='sudo rm -rf /' # end aliases # other commands I wish to replace that block of text with some ...
0
votes
1answer
185 views

Remove the exact same matching lines with sed

I have this bash script: sed -i -r '/deb http\:\/\/httpredir\.debian\.org\/debian jessie main/d' /etc/apt/sources.list sed -i -r '/deb http\:\/\/httpredir\.debian\.org\/debian jessie\-updates main/d' ...
0
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3answers
193 views

Shell pattern matching and arithmetic operators (+ - * / %)

This looks so simple but it isn't: [[ "1234+5678" =~ [0-9]+(\s*(\-|\*)\s*[0-9]+)* ]] && echo $? returns a 0. However, it actually should not do that, as only minus (-) and multiplication (*) ...
2
votes
1answer
229 views

Match a number range with grep

I need to find all processes that have in their names a number between 100 and 200 inclusive. I tried ps -ef | grep xclock -bw '[1-2][0-9][0-9]' but that includes 299. How to suppress it and ...
0
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2answers
418 views

Extract just the hostname and port number from tnsnames.ora file

I would like to give a hostname, and get a port number in return. My tnsnames.ora file looks like: DELUCA = (DESCRIPTION = (ADDRESS = (COMMUNITY = TCP.world)(PROTOCOL = TCP)(Host = ...
0
votes
1answer
59 views

Find directory names with N occurences of a set of characters

Sorry in advance, I know there are hundreds of posts about find, but I genuinely don't understand what's happening here and haven't been able to find a definitive answer to this question: how to match ...
0
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2answers
135 views

Grep for regex in basename but return wholename

So say I have a list of files in a text file: ... /foo/barfoo /bar/foo/foobar /foobar/bar/foo ... I have a script that will search through this text file and, much like the locate command, I want ...
0
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3answers
52 views

match same lines [closed]

I've a file for which I need to know if it has entries which are the same The file contains entries like this: dn: cn=ccb2fa1a-6efb-4f29-b18b-72e226d76935,ou=Named,ou=Identities,ou=Active,o ...
0
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1answer
71 views

What does “\(\)” stand for in this command: grep(“-(mean|std)\(\)”, x[,2])

Need to know about the function of \(\) in grep("-(mean|std)\(\)", x[,2])
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2answers
80 views

Find all characters “[1-777])” at the beginning of the line

Pseudocommand perl -pe 'g/^[1-777])/g' data.txt where I try to all numbers at the beginning of a line with ")" following them etc 1), 67) and 777). Data where all question numbers should (etc 1), ...
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3answers
82 views

Match beginning of a line with something there?

I want to match the beginning of lines where the line contains something. Command in Perl/Sed 's/^.?/\section{}/g' but the problem here is that it replaces also the first character of sentences. ...
3
votes
1answer
771 views

Regex for crontab validation

I need to check in bash whether an entry into the crontab file is valid. Is there a crontab command switch? I can extract individual lines and try to control individual items through regex. But I ...
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4answers
1k views

How to use regex to match a pattern which does not have a specific string at the end

How to use a posix bre or a posix ere regex to match a word which does not have bak at the end. I want to do a ls | egrep '<regex>' to find all files which DO NOT have bak at the end of ...
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2answers
151 views

How to filter content between specific keywords using grep?

I got a bunch of files, and I want to find out the content between two tags st and et. if I use grep "st.*et" files, I will get these two tags involved in the result. Such as st Hello world! et. But I ...
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2answers
122 views

searching for the c++ in a string (regular expression)

I want to find if a string contains c++ in it (regular expression). what pattern should I use in grep function in R? This is my error: Error in grep(pattern = "c++", x = df[trow, "modeling"]) : ...
0
votes
1answer
44 views

How to integrate awk parameters in awk range pattern

I need to get something like this #Batch Job - AB1234 texts texts texts texts texts #-------- I used awk '/#Batch Job.*AB1234/,/#--.*/' filename and i went well. But then when I tried to ...
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2answers
321 views

UltraEdit - regular expressions replacement

I was trying many different combinations without success, at this point I would be really grateful for your help. I need to replace this end of the line multiple times (around 300) and it would be ...
2
votes
4answers
73 views

remove the content from the beginning to the first blank line

I'm trying to remove the content from the beginning of the text to the first blank line. --($:~)-- cat example.txt pedro pablo juan francisco emiliano martin So, I would delete: pedro pablo ...
5
votes
6answers
593 views

sed command to swap characters

My input file layout is: mm/dd/yyyy,hh:mm,other fields I need to format it as: yyyy-mm-dd hh:mm:00,other fields sample input: 01/02/1998,09:30,0.4571,0.4613,0.4529,0.4592,6042175 ...
0
votes
3answers
7k views

How to detect end of line with sed

I'm looking for a way to only execute replacement when the last character is a newline, using sed. For instance: lettersAtEndOfLine is replaced, but this is not: lettersWithCharacterAfter& ...
0
votes
5answers
3k views

How to grep an xml block in an xml file using a keyword in ksh

I have a file Sample.xml which contains a lot of services inside it and the structure looks like this Notes: I cannot use any XML parser tool as I don't have permission , read only My xmllint ...
0
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1answer
183 views

How to parse through a .dat file and get patterns such as timestamps and file size of a .jar file declared inside

I want to compare the size and timestamp of the following jar files in separate directories. First data is fetched by: grep -Eo ...