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

learn more… | top users | synonyms (1)

3
votes
3answers
4k views

Yum regular expression or wildcard search?

Fedora documentation says: 5.2. Advanced Searches If you do not know the name of the package, use the search or provides options. Alternatively, use wild cards or regular expressions with ...
3
votes
3answers
4k views

Replacing string in all files found by grep. Can't get it to work

I'm trying to do what title says. So I find all needed files with grep: grep --include=\*.{php,ini,conf,sh} -ril -P "'([\d\w\-\_\.]+)(@domain.com)'" '/var/www_data/somepath/' Now I assume it's ...
3
votes
1answer
4k views

Get all regex matches between two patterns and print them to file

I've got a file with a bunch of long lines. I'd like to grab every group between two patterns and print them to a new file, one match per line. I could manage to do this with Python, but I'd prefer ...
3
votes
5answers
282 views

Regex match in CLI

Is there something like a logical for the cli? I want to achieve this mv -t newfolder *.(png|jpg) so that alls jpg and png files are moved into newfolder. I know it could be done with mv -t ...
2
votes
4answers
8k views

Match multiple regular expressions from a single file using awk

I'm trying to parse a HTML file using shell scripting. There are 4 different regular expressions that i need to catch: name= , age= , class= , marks=. Using grep "name=\|age=\|class=\|marks=" ...
0
votes
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), ...
0
votes
2answers
117 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 ...
10
votes
2answers
1k views

grep: display filename once, then display context with line numbers

Our source code has error codes scattered throughout. Finding them is easy with grep, but I'd like a bash function find_code that I can execute (eg. find_code ####) which will provide output along ...
6
votes
1answer
4k views

Why do I have to escape a “dot” twice?

I know that we can escape a special character like *(){}$ with \ so as to be considered literals. For example \* or \$ But in case of . I have to do it twice, like \\. otherwise it is considered ...
5
votes
2answers
2k views

Lowercase all but the first (Uppercase) letter from UPPERCASE in cyrillic

To make all letters a lower case except the first letter. The first letter would look like "Uppercase" after I changed (from UPPERCASE in cyrillic). The rest (not UPPERCASED) leave unchanged. I'm ...
4
votes
2answers
83 views

BSD sed: Replace only the Nth occurrence of a pattern

Using BSD sed; How can I perform the following substitution?: Before: hello hello hello hello hello hello After: hello world hello hello hello hello In other words; how can I replace only the ...
4
votes
1answer
79 views

Bash regular expression pattern matching spaces, within double brackets test, using “~=” operator

Simply said, I just can't find a way to match a variable against some pattern containing spaces. Here is what I expected to work (echo 'ok' string) item='foobar baz' pat=".+bar baz" if [[ "$item" =~ ...
4
votes
4answers
2k views

How can I find and replace only if a match forms a whole word?

My script is: n="y" while [ "{n}" = "y" ] if [ $n == "n" ]; then break; fi echo "n is $n" do read -p "Enter the word to find = " word read -p "Enter word to replace = " replace ...
4
votes
2answers
714 views

Find and regex

What am I doing wrong with this find expression? ; touch ook ooks ; find . -name 'ook' -or -name 'ooks' -type f ./ook ./ooks ; find . -name 'ook[s]?' -type f [returns nothing] ; echo $? 0
4
votes
1answer
978 views

Is there a tool in linux that allows multi-line regex expressions?

I'm wanting to find the results of a multi-line regular expression in linux. I tried grep, but like most linux utilities it's line based. Is there something similar that allows me to search across ...
4
votes
1answer
368 views

Trouble with grep -o regex

I'm trying to use a grep command with the --only-matching flag, but it's not behaving as I would expect it to. This command: echo "1/2/3/4/5" | grep -oE "^([^/]+/){0,2}" Gives this output: 1/2/ ...
3
votes
3answers
751 views

bash - extract filenames from html file containing multiple links

I have downloaded an html file autogenerated by a script on a webpage. The file contains multiple links, including links to images I am trying to extract the full names of the images, for example ...
3
votes
3answers
681 views

sed - how to (not) match unmatched brackets

How can I do my operation only on lines that close their brackets? For example I want to change ".is" lines and add a bracket but not for lines with unclosed brackets. so these are changed ...
3
votes
1answer
452 views

How to join vCards lines

vCard uses a special way to split long lines: At 75 characters, insert a DOS newline and a space. Joining therefore means to replace all occurrences of the sequence "CR, LF, space" with an empty ...
2
votes
2answers
80 views

Insert “return 0” between all braces in a file?

I'm setting up a fairly large (~50 functions) test library in C++. I forgot that the functions have to return integers. I actually forgot to put a return type at all, how dumb is that? I added the int ...
2
votes
1answer
5k views

How to grep exact word with only space as word separator

For Example: I have file like following: AA ABC-AA-AA AAA ABC-AA ABC.AA ABC AA ABC.A AA If I use grep -w "ABC" file1, I am getting all the lines. But I should only get 3rd line: ABC.AA ABC It is ...
2
votes
3answers
7k views

grep to find words with all vowels

Using grep -E and regular expressions I need to find words containing all of a group of characters in no particular order. For instance a word containing all vowels (aeiou) however the vowels can ...
2
votes
1answer
84 views

Context of the matching regular expression

I'm using egrep with the -o option in order to just get the matching part of the line, e.g. cat /usr/share/dict/words | egrep -o '(aa|ii)' Now I'd like to see some context of the match, i.e. a few ...
2
votes
2answers
490 views

can regex capture groups be used in GNU find command?

With the GNU find command (GNU findutils 4.4.2), a regular expression can be used to search for files. For example: $ find pool -regextype posix-extended -regex ...
2
votes
4answers
8k views

How can I find all files in a folder that contain a match of a regular expression in the file name?

I'd like to find all of the files in my home folder on Linux (Ubuntu, in this case) that contain a match a particular regular expression. Is there a simple Unix command that I can use in order to do ...
1
vote
2answers
77 views

Complex sed Command with AND/OR/NOT

I have a bunch of php files which have many select commands. In each query i want to insert a coloumn variable admin_id = '$admin_id' i.e. if the query is select * from users where abc='xyz' and ...
1
vote
2answers
219 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 ...
1
vote
2answers
102 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, ...
1
vote
1answer
118 views

How can I use regex to extract the text following two conditions into a variable?

I'd like to extract a setting for a given host in the ssh_config file and put it into a variable. Host mysite HostName 123.1.1.1 User myuser Port 13245 GSSAPIAuthentication no ...
1
vote
3answers
2k 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=" /> ...
1
vote
3answers
4k views

How to print only the first match with grep

I'm trying to grep username: users | grep "^\b\w*\b" -P How can I get it to only show the first match with grep?
1
vote
1answer
2k views

Difficulty making a regular expression to find at least 2 occurrences of a character in a file

I have a file containing random codes. Each code has ten characters in it, and I am trying to grep codes in the file that have at least 2 occurrences of a character. I am doing this: grep DD* ...
0
votes
2answers
206 views

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 ...
0
votes
1answer
232 views

Replacing all `&` but not the one in XML entity `&amp;` with `#` with sed in a given XML tag

I needed to replace all & with #, inside and only inside the <faultstring> ... </faultstring> tag. Additionally, the & in &amp; should not be changed. Sample input: ...
0
votes
2answers
431 views

Regex and patterns on a ksh command line

I'm wondering what's the difference between using * and .* in a regex string. I guess, * stands for "0 to n characters" but I don't see what .* stands for. For example, what is the difference ...
0
votes
1answer
175 views

How to ask for specific parameters with grep?

I need to look in /usr/share/dict/words for a 5-letter word that starts with d or D, followed by a lowercase vowel, and ends with s. I have tried everything but to no avail.
0
votes
1answer
2k views

How to highlight the whole log-line in color with multitail

I'm trying to use multitail to tail logs with color highlights. I defined a custom color scheme in multitail.conf, something like this: colorscheme:my-color cs_re:red:^\[E cs_re:yellow:^\[W ...
0
votes
2answers
1k views

Curl and grep html text

Is there a way to grep html text from a curl request and output grab the value that is between two html tags? More specifically the input value of a form?