I am new to using regex and having some issues understanding how to extract a group from a regular expression. I have a text file (example.txt): I am trying to extract the “5.2.1” only from the libpackage line and put it into a variable for a bash script. I have tried doing But it gives me the entire line instead
Tag: regex
How to match and cut the string with different conditions using sed?
I want to grep the string which comes after WORK= and ignore if there comes paranthesis after that string . The text looks like this : So, desirable output should print only : So far , I could just match and cut before WORK= but could not remove WORK= itself: I am not sure how to continue . Can anyone
bash – print regex captured groups
I have a file.xml so composed: I need to extract the following information: mayor_and_minor_release_number –> 1.0 patch_number –> 13 suffix –> -alpha I’ve thought the cleanest way to achieve that is by mean of a regex with grep command: I’ve checked with regex101 the correctness of this regex and actually it seems to properly capture the 3 fields I’m looking
Skipping a part of a line using sed
I have a file with content like so – @1: 00001109 Each line is of the same format. I want the final output to be @1: 00 00 11 09. I used command in sed to introduce a space every 2 characters – sed ‘s/.{2}/& /g’. But that will give me spaces in the part before the colon too which
Searching two patterns in files that appear in the same file but may not appear on the same line
From a directory, I need to find all files that contain a decimal numbers say 42.7 AND the keyword “foo” or “goo”. How could I achieve that? Suppose I have a directory with three files The search command should give file1.txt and file3.txt. What is a search command to achieve this? i searched for the solutions but all I could
Remove ” and n using sed
How to replace the below text using sed or in any other method. I need to replace the above to be like Answer A or . needs to be escaped in regex pattern. You may use this sed: You may consider this awk to remove ” and n characters anywhere in the file:
Bash regex for same sender and receiver with backreference
I try to make a regex (important that ist a regex because i need it for fail2ban) to match when the receiver and the sender are the same person: What am I doing wrong ? Answer You might use a pattern to match the format of the string between the brackets with a backreference to that capture. Explanation from Match
how to edit a line having IPv4 address using sed command
I need to modify an ntp configuration file by adding some options to the line containing Ip addresses. I have been trying it for so long using sed command, but no able to modify the line unless i don’t know the IP addresses. Let say, i have few lines as, server 172.0.0.1 server 10.0.0.1 I need to add iburst option
How do i extract some particular words from each line?
The text file has many lines of these sort , i want to extract the words after /videos till .mp4 and the very last number ( shown in bold ) and output each filtered line in a separate file Lets say for example the text file content is .. The output should be Answer You may try the below regex:
list tables from mysql dump file with sed
I have situation where I need to extract tables list from mysql dump file. I tried that with sed but got this error what did I miss in my regexp? Answer Since you are using Linux, and you need to get all strings inside the first backticks after DROP TABLE, I’d suggest using grep with a PCRE regex like See