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

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Finding all kinds of extensions referenced in a html file

Here is my problem statement : There is a folder with many html and text files. I need to recursively go through each one of them and find all kinds of file extensions referenced in these html/text ...
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232 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 ...
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134 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.
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Regular Expression for finding double characters in Bash

I am looking for a regular expression that finds all occurences of double characters in a text, a listing, etc. on the command line (Bash). Main Question: Is there a simple way to look for sequences ...
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111 views

regex suggestion

echo "223255/12345678 " | grep '[0-9a-zA-Z/\-\?:\(\)\.,"\+]{1,34}' According to the regex, it can have any of 0-9 a-z A-Z / - ? : ( ) . , " + of upto 34 chars in any order. Am I ...
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53 views

Bash detect ascii art [closed]

For bash script, is there a easy way to detect if a text contains ascii art? An example of ascii art:
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31 views

Using regular expressions to search a word list. Finding 2 letter words instead of 3. Why?

I am studying regular expressions and I am stumped. Here is my process so far.... I downloaded this file. wget http://www.mieliestronk.com/corncob_lowercase.txt mv corncob_lowercase.txt words.txt ...
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40 views

What is the meaning of (^| )ABC( |$) as an extended REGEX ?

I came here across the command grep -E '(^| )ABC( |$)' file1 I am confused how to interpret the regular expression therein, because I know the ^ and $ character as beginning and end signifier, but in ...
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53 views

How to find with grep lines that end in a certain string?

I know that to find a REGEX that ends in a certain string I have to write "string$". Although I tried the following variations of grep : cat foo | grep "string$", cat foo | egrep "string$", grep -E ...
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104 views

Using sed to remove digit separation commas enclosed in quotes and quotes itself from CSV? [duplicate]

How can I can use sed to remove from before-last column the group digit char comma and quotes itself? Please note that in the sample below the target column is not contained in double quotes. ...
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44 views

Regex gone Wrong

I am using a Bash script to use awk to look for this: (0010,0080) The awk will generally look for any numeric value seperated by a comma in between parenthesis. I have done everything I can think of ...
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82 views

Strip the file base name, keep the directory part

I have a string which looks something like this dir/subdir/othersubdir/file.txt But it can also look like dir/file.txt or dir/subdir/file.txt Now, I am making a script where $P is the full ...
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704 views

Grep finding phone numbers in files

How would I look for files in the /etc directory (but not subdirectories) that contain a standard United States long distance phone number, written using the pattern of 1-###-###-####, where each # is ...
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44 views

Expansion of *,#,% - What do they mean? [duplicate]

for j in * .* ; do cp $j ../$name-S$i.gid/${j%%. * }$i.${j#*.} done Could someone tell me what this for loop does? What do *, % and # mean? ($name is a path of a directory in which there are ...
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45 views

Grep lines from foe to foe2 (not included), regexp

The file is organized in entries of the form: foe, 1.... 2.... 3.... foe2, 1.... 2.... All sub-items begin with four spaces, and then text or number item. All entries like foe, begin ...
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738 views

How do I join the next line when a line matches a regex for whole document in VI?

As title, for example, I have lines like abcdefg join! abcdef no join abcdefg join! If a line matches regex ^a.+g$ then I would like them to be joined, so it would be: abcdefgjoin! abcdef no join ...
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48 views

sed how to do “or”

I have the following two lines that work ok: /\.to <\=/ s/<\=/be <\=/ /\.to_not <\=/ s/<\=/be <\=/ I would like to combine them and I tried: /\.to( |_not )<\=/ s/<\=/be ...
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121 views

Replacement in VIM with regular expression matched part unchanged

Suppose I want to append two digit numbers in my file with "some_thing". Like from this: 12 23 45 to 12_something 23_something 45_something How can I do this using regular expression ...
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34 views

Vim: Count all occurrences (including multiple on the same line) of char or word

I try to count all occurrences of a char or word in a file with Vim. This means multiple occurrences of the same word in the same line should be taken into account as well. This has been discussed in ...
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23 views

Interactive less search with wildcards [duplicate]

I'm using less to view a large file and I want to search for a pattern with wildcards — e.g., " x 1??" where ? is any character. Does less support that, and if so how would I do that ...
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29 views

How to search parenthesis by ack

I want to search for a parentheis ( using ack, but neither using ( nor \( worked. The first one ("(") is recognized as a multiple line command. The second one ("\(") is treated as an invalid regular ...
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41 views

What is the Difference between Regex `[]*` and `[]+`?

I started learning regex recently. I know that * modifier means match 0 or more times while + modifier means match 1 or more times. However when you use these modifiers with square brackets, how ...
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99 views

regex find replace strings starting or beginning with backslash

I have a compilation album in my music library that has song titles in the form of ARTIST/ TITLE, which is making it really difficult to cp or mv these files because of the slash. So I'd like to ...
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58 views

Regex long list of numbers

What is the command in Linux to find the regular expression e for every number from 37 to 200 included in a list with such numbers?
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404 views

How to escape unbalanced brackets or slash in sed?

I'm trying to use sed, but my pattern contains [] brackets and slashes (/). I've tried quotes, but it doesn't help. How do I escape it? Examples: $ sed -i'.bak' "s/^includes[] =/;includes[] ...
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Shell pattern matching vs. regular expressions occurence [duplicate]

I am relatively new to Unix, and I stumbled across one curiosity. Some shell constructs like case or find, employ pattern matching, but it is not quite regex. Other commands, like ed, sed, vi, and ...
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441 views

Want to replace the words with space in multiple files using SED commmand [closed]

Want to replace the words with space in multiple files using SED commmand I have a word as 'Danny' with single quotes in many of my files in multiple directories which I want to change to 'Danny ...
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2k views

grep: match pattern on a particular position

I need to match a pattern with grep, only if it starts at position 16. Lets suppose I want to match the string ' pattern' (starting with space) the following should match bla bla bla bla pattern ...
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55 views

Piped search queries in vim or less

I would like to be able to search a log file for lines that being with ^2014-02-18 15:30:[0-9:,]* and have UserName:someguy much later in the same line. I am sure I could do a regex to include any ...
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107 views

All occurrences of a regex get removed without using the “global” modifier

I have the following text in the file sentence.txt Linux refers to the family of Unix-like computer operating systems that use the Linux kernel. Linux can be installed on a wide variety of ...
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4k views

sed - how to exclude multiple patterns in the match

I have currently a set of seds that's working well except for one thing. The particular expression I'm having an issue with is: sed -i '/[^}.to]\.to[[:space:]]/ s/\(\S\)/expect(\1/' ...
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343 views

Regex awk to Cisco Interface

I would like to know if have some Sed/Grep or Awk regex to parse Cisco interface section, with specific attribute, like bellow. Content of file.txt ! interface FastEthernet0/1 no ip unreachables ! ...
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68 views

Help with understanding a regular expression

I have this regular expression \\..\\{3\\}$ I want to understand how this expression works to match a string. My thought is that it matches any 8 characters at the end of the line. Is that how this ...
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154 views

regex, only the first occurence

I have a pipelined output from free -o -m | awk '{print $4}' I want take step by step two numbers the first and the second line. So i need two regexes. I tried with ^[0-9]{1,3}$ but this match all ...
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Egrep: contains and does not contain

egrep -i '12-12.*\swarning' log.file | cless The above will produce two lines with the date 12-12, followed by random characters, a white space, then Warning and more text. 2011-12-12 textetc ...
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263 views

python regex equivalent of kwrite [ ]+ and [0-9]+

I've never been good at regular expressions. When ever I read about them, I sort of get a headache, get up from my desk, and forget what I'm doing. Attention difficulties. But when I finally started ...
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847 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?
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35 views

What is the email matching regex in basic regex for grep?

I created a text file and put some email addresses in it. Then I used grep to find them. Indeed it worked: # pattern="^[a-zA-Z0-9]+@[a-zA-Z0-9]+\.[a-z]{2,}" # grep -E $pattern regexfile but only as ...
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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 ...
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42 views

Regex for matchng anything between parenthesis

I have the following regex so far: printf "this is (test.com)\n" | grep -Po '(?<=\().*(?=\))' The above regex will print the desired output, which is test.com As far as I am adding new ...
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24 views

Coordinates X237595Y81600 to X2375Y8160

I have create a gerber file and it has lines inside which look like this: X90095Y15350 X100095Y15350 X110095Y15350 X120095Y15350 X120095Y25350 X110095Y25350 X100095Y25350 X90095Y25350 X80095Y25350 ...
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33 views

is there a way to see a listing of packages ONLY from Debian-experimental?

I am on Debian testing/Jessie and I have debian-experimental as well as in my /etc/apt/sources.list. So I am looking to list packages in two ways :- a. List all the packages which are in ...
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427 views

Shell script to add or replace block of text?

I'm looking for a shell script (Bash) that adds or replaces copyright text at the beginning of the file (for .c and .h files). It should search and add or replace the copyright text block for all the ...
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61 views

combining grep ignore and matches

I would like to grep a file to find all instances of the text fn1 that don't have the word call in front of it and print out four lines before and after the matches (even if the surrounding lines have ...
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137 views

Bash regex string manipulation bug

I have an issue with bash and its regex match ability that I for now think is a bug in bash but could also be me having missed something obvious. I hope it is the latter. I have made this function in ...
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62 views

No output from grep -P 'com\K\w+'

I have a source file saved off the internet which has various links I want to pull data from. For example https://blahblah.com/uniquetext I'm using grep -oP 'com\K\w+' source.txt > list.txt ...
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How to make my regular expression accept zeroes in the input?

I wrote a regex that accepts numbers between 0 and 999,999,999,999.99. Commas are optional, but, still should accept value not higher than 999999999999.99. I wrote one, but, there are two flaws in it. ...
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32 views

regexp in find to locate only

I have csv file (products.csv) with product numbers $ cat products.csv | head -3 2.20 2.21 2.22 in another directory I have thousands of product images in subdirectories. I need to locate product ...
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62 views

How can I parse my String using regular expression to get only certain number of matches? [closed]

I am currently using this following regular expression to split my String into groups. ^([a-zA-Z0-9]*)(\[([a-zA-Z0-9=]*)\]){0,1}@([a-zA-Z0-9]*)$ Pty[R=4]@ID I am getting four groups 1) Pty 2) ...
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310 views

How to match date in Perl — assuming UNIX regex is the same as Perl's

I want to match dates of the form Monday May 26 My attempt to do this is the following: /(.*day Jan.*|Feb.*|Mar.*|Apr.*|May|Jun.*|Jul.*|Aug.*|Sep.*|Oct.*|Nov.*|Dec.* [1-31])/ The regex form in ...