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Questions tagged [regular-expression]

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

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2answers
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Unix shell : substring with regular expression [on hold]

I have this text: 1234 I want to use a regex to select all except the first digit (in this case 1) - so a pattern that selects 234 How can I do this? I can't use variables, only regex. And also I ...
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0answers
32 views

sed command to insert between two strings that are returned from another sed command

I have a YAML file that's about 25K lines and I have about 450 instances where I need to insert between two specific lines. Here's an example of the file entries: - changeSet: id: ...
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2answers
30 views

Regular expressions in grep

The man page for grep reads (emphasis mine) REGULAR EXPRESSIONS A regular expression is a pattern that describes a set of strings. Regular expressions are constructed analogously to ...
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0answers
47 views

Complex string replace - multiple files, multiple different strings, must include certain text

I have a number of XML files (Atlassian Confluence space exports FYI), that I need to parse through to replace certain strings, as long as the line begins with a set string. Here is an example of a ...
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4answers
54 views

How to extract the CSV file name from each line of this file

I have a file which contains lines like those: -rw-rw-rw 1 root root 6379 May 24 2016 test1.CSV -rw-rw-rw 1 root root 23249 May 25 2016 test2.CSV -rw-rw-rw 1 root root 2995 May 26 2016 test3.CSV ...
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1answer
30 views

\back slash charectar and . in grep

I am confused about the backslash character \ and single quotations inside grep. From my understanding it preserves the literal meaning. For example if I do echo 'This is \., it gives me This is \. ...
2
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1answer
172 views

Regex in IF condition in awk

I have awk script file as below. I need to add another condition in the if statement to check if the string contains atleast one alphabet. How can I add the extra condition to the present if statement?...
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2answers
34 views

grep STOP regex replacing -A option

I'm looking/searching for a way to make grep stop when finding the "|_" specific string after having found the search string. for example, i want to print ONLY the lines starting 2 lines above "...
3
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2answers
693 views

Merge two greps into single one

I need to extract an ID from the output of another command. Currently my extracting command looks like: someID=$(command | grep -oP '(?:^Successfully\sbuilt\s)([\da-z]{12}$)' | grep -oP '([a-z\d]{12})...
3
votes
2answers
56 views

Using regular expressions in “less”

I'm trying to use a regular expression in the man page of Bash by using less. I press / in less to enter a pattern, and I type z and press the Enter. I expected it to not match upper-case z (Z), but ...
3
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0answers
44 views

Renaming files with vidir (moreutils)

I'm trying to use vidir from the moreutils package and I have the following issue: When I load the files I want to rename with vidir like this: $ vidir or like this: $ find -type f | vidir --...
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2answers
39 views

Need regex to replace the whole line, but the last optional character

It sounds like it should be trivial task, but I cannot figure it out, so I decided to ask. I need to replace the whole line, but optional last character. For instance, I want: abcd to become efgh but ...
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0answers
24 views

Rename multiple files, removing text before prefix [duplicate]

I have 70 ish csv files that look something like: C03-10dfg-PI-35.csv C03-fgfg-PI-36.cvs C03-dfdf-PI-37.csv .... .... .... I want to rename all files to remove everything before PI. Outputs: PI-35....
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3answers
50 views

In a bash shell script, how to rename multiple files, keeping only the numbers and the extension of the original file names?

I have a directory with a bunch of files with names like this: generic name- dd -01 _.txt generic name- dd -02 _.txt generic name- dd -03 _.txt generic name- dd -04 _.txt And I want to rename all of ...
4
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2answers
94 views

When and why did ^ and $ take on their meanings of “beginning of line” and “end of line?”

Many command-line tools (grep, flex, etc.) use the ^ symbol to denote "beginning of line" and the $ symbol to denote "end of line." When did this convention arise? It seems perfectly reasonable to ...
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1answer
53 views

How to match string in file

I'm trying to reproduce this code in Python to Bash import re w = open("filetest.txt") for item in re.findall(r'STRING:\s*(.+)"', w.read()): print item In Bash, but I do not know if it's correct, ...
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1answer
41 views

grep to find lines that contain six or more non-vowel characters in a row

Using grep and regular expressions, I need to output all lines in a file that contain at least six characters in a row that aren't vowels. This includes any consonants, punctuation, numbers, etc.
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3answers
62 views

How to test if a folder exists using regular expression in Bash?

as all know we can check easily if folder exists by the following bash command [[ -d /opt/presto-server ]] && echo folder exist but when we have folder as /opt/presto-server-32.34 then how ...
2
votes
1answer
35 views

Recursively find directories but do not print subdirectories of matches

Considering the following directory structure: dir1 [domain.com] foo dir1 subdir1 subdir2 FooFile dir2 [domain.com] foo dir2 subdir3 [domain.com] foo dir3 subdir4 ...
1
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2answers
50 views

append brackets to all constants beginning with L:: where it not exist on end

I have many PHP Files where I need to add on end "()" to every constant beginning with "L::" which don't have on end "(". It should by applied to all *.php including subfolders) : L::WHAT_EVER <?=...
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2answers
78 views

how to deal with sed if Argument list too long

Trying to apply the following command: sudo sed -i "s/auth-user-pass/auth-user-pass pass.txt/g" *.ovpn But i keep getting the following error: sudo: unable to execute /bin/sed: Argument list too ...
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1answer
41 views

Is there any initiative to transition all shell globs into standard regex?

I see many imagination between shell globs (wildcards) syntax and standard regex. Is there (or was there) any initiative to transition all shell globs into standard regex? By that I mean, using ...
0
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4answers
51 views

how to let part of the regex (that is variable) be matched literally, ignoring control characters?

I got some filenames containing characters that are regex special control ones. I need to prepare a regex that considers all these characters literally. Simplified test case: strFilenameOnDB="...
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3answers
70 views

What does the following number-processing sed code mean?

I came across a code in script which add ',' after every 3 digits from backwards. the code only considers numeric data. Following is the code. sed 's/\(^\|[^0-9.]\)\([0-9]\+\)\([0-9]\{3\}\)/\1\2,\3/...
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1answer
53 views

How to grep for a particular string?

I am trying to get a string that matches the following pattern: starts with foo and finishes with bar. grep -e "^foo*bar$"
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3answers
291 views

Extract substring according to regexp with sed or grep

In a (BSD) UNIX environment, I would like to capture a specific substring using a regular expression. Assume that the dmesg command output would include the following line: pass2: <Marvell ...
1
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0answers
58 views

sed command is replacing the replaced text?

I am writing a bash script to rename icons. Specifically I am trying to change "icon-close-m" to "icon-close icon-size-medium" in HTML files. (though it could contain any substring besides "close", as ...
1
vote
1answer
37 views

Why is this regex not working in awk?

I have a text file as such: Attribute 1.............. : attribute value Encode Date............................. : JUL 2007 Attribute 22076.......... : attribute value` I want to extract the JUL ...
0
votes
1answer
42 views

Multiple replacements using regular expressions in python

Can I use regex in python to have multiple types of substitutions? Like in this string "hello, this is me" I want to replace 'hello' with 'hi' and 'this' with 'its'. Can I do it in a single line? Or ...
0
votes
1answer
25 views

How to specify regex quantifiers with mawk?

I'm familiar with the concept of specified bounded regex quantifiers as follows: Quantifier Legend Example Sample Match {3} Exactly three times \D{3} ABC {2,4} ...
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2answers
47 views

Grep in bash issues

Sample string: --000000000000f104a6057d4a0a10 Here I need to get for sure: "--" Same files also contain a lot of similar strings; ------=_, --=_ , -----------, --< which currently also get ...
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2answers
27 views

split file lines by regex delimeter

I want to split each line from input file by a non-alphanumeric regex \W and print all the split chunks in the output file like so: Input file: www.wifi.in.ua YI-HondBrychka Output file: www wifi ...
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2answers
53 views

Can't replace my regex matches

I can filter files, I can can stream the matches of my regex ... However, I need to remove exactly that, from a large file. Regex:^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$ sed ...
0
votes
1answer
100 views

Regex expression for IP address/CIDR in bash

I want to check if the user input is a valid IP address/CIDR in bash and I am using regular expressions to do that. So valid CIDR should be 0-32 and for IP from (1-254).(1-255).(1-255).(1-255)/(1-32) ...
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2answers
103 views

How to mass rename files with regular expressions [closed]

I have a bunch of folders in a directory with files in them. Most of the filenames have region codes (retropie), and the scrubber will not match roms with single letter region codes (u,j,e,etc.). I ...
0
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4answers
90 views

grep IPs and port number into one line

Using grep and cut I have returned the IP and ports of the nmap scan result which looks like this: 192.168.1.221 80 443 192.168.1.223 25 Desired output: 192.168.1.221:80 192.168.1.221:443 192.168....
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2answers
73 views

grep for single back slash

I am trying to grep for the mount output to see the options for the root directory. Why the following pattern (whitespace before and after a slash) is not working (with and without extended grep) /...
2
votes
4answers
90 views

Removing (possibly nested) text quotes in command line

I need to parse large amounts text in command line and replace all (possibly nested) text quotes with spaces. Quotes are marked with specific syntax: [quote=username]quoted text[/quote]. Example ...
0
votes
0answers
30 views

Commenting out a specific host configuration in a Nagios configuration file

I have lots of Nagios configuration files like the one below in a directory, and I need to remove a host from monitoring. define host{ host_name nmo use aix-server alias hostgroups +...
1
vote
5answers
50 views

remove all lines with nullbytes/corrupt data

So I recovered a text file from an old hdd, but I failed to completely recover all of the data. The data that wasn't correctly recovered has returned as null bytes. How can I remove every line from ...
2
votes
2answers
46 views

how to find the real path of folder with regular expression

presto is distributed SQL query engine , and when we installed the presto then it should be created the following home folder /application/DB/presto/presto-server-0.216 so we can say that in ...
0
votes
1answer
67 views

Bash regex and IFS split

I have the following problem: I want to extract text that is inside brackets from a string (with or without the brackets). My string looks like this: STR="[1] [2][345] [678 9] foo bar" I initially ...
0
votes
0answers
45 views

Remove all words from a file except certain words

I have a file which represent a list of SQLs where caluses. I want to remove everything that is not the columns names, and, or and where(case insensitive). In addition if it can also remove new lines ...
0
votes
1answer
74 views

sed: escaped square closing bracket does not match

Goal: replace ![alttext](url.png) with <img src="url.png" alt="alttext">. The ! and (...) parts work fine, it's the [...] part that I can't get to work. As a simple example, I want to match ...
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2answers
96 views

Use FIND with MV to rename files. Delete the found string then prepending it to the filename?

find . -type f -name '*authors-name-string*' -exec bash -c 'mv "$0" "${0/authors-name-string/}"' {} \; I am trying to rename files nested in several layers of directories that contain an author's ...
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votes
2answers
41 views

* in awk (metacharacters)

Can you explain me how * works? I have an input: U 8649 275 Asia Canada 3852 25 North America China 3705 1032 Asia USA 3615 237 North America India 1267 746 -Asia ...
4
votes
1answer
381 views

Awk - metacharacters

What is the difference between [+-] and [-+]. It seems to me doing the same thing. And what does [A-Za-z-]+ do? Or I tried awk '/[^-]/' contries and I expected nothing as an output.
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4answers
416 views

Why does regex `“\.pdf”` match `/…/pdf…/…` in gawk, but not in mawk?

From How can I extract only the pid column and only the pathname column in the lsof output? awk '{ for (i=9; i<=NF; i++) { if ($i ~ "string" && $1 != "wineserv" && $5 == "REG" &...
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0answers
82 views

How to improve this 'sed' search & replace command?

How to search and replace recursively through multiple files in a directory, using essential tools installed in mostly any Debian/Ubuntu machine? There are multiple answers in Stack* where to find ...
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votes
1answer
52 views

How to grep out all rows not matching the given pattern

I have csv files received on Linux, they come with their own different patterns, one example here: $ head test.csv wampproduct,wamp_date,wampregion,region_search_phrase,wamp,date_pull,end_of_month_dt ...