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

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extracting ip address from a file [closed]

I'm trying to extract all the IP address from a file. FILE *>i85.95.2.160/29 172.16.24.4 0 200 0 64515 4445 15412 i *>i85.112.80.0/28 172.16.24.4 0 200 ...
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Parsing csv with sed and perl one-liner?

I have a web server which stores configurations to PostgreSQL, and I plan to retrieve information from a certain table and then later parse it into csv format. PAYLOAD <?xml version="1.0" ...
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Using a variable in a regex

How can I use a variable string in a regular expressions while read line do if [[ line =~ *"$key"* ]]; then echo line fi done < "$filename" $key is a string ...
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Differing outputs of the commands “ls .*” and “ls *.”

The command ls .* when run gives as output the following : All the files in the current directory starting with a . (hidden files) All the files in the hidden directories present in the ...
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use search result in replace statement with vim substitute

I know this is gonna be a stupid question, but I've tried here, google and the official documentation. I've got a file with a whole heap of words of the form 'foo' and i want to change them to ...
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202 views

Ignore lines containing a capital letter

Why does the following command still return some lines containing a capital letter? aspell dump master | grep ozz | grep -v '[^A-Z]'
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154 views

Understanding -regex with GNU find

Background I have what I think should be a simple case. I want to find all files with "cisco" in the name and do something with those files (via xargs). Finding files with ls Before I use xargs, ...
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2answers
338 views

rsyslog: make %syslogtag% equal length

I have rsyslog configured to log in the following format: $template long-iso,"%$NOW% %timereported:8:15% %syslogtag% %msg%\n" which produces logs like this one: 2013-12-14 15:59:39 ...
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Using BASH versus ASH on Synology

The majority of my photo files have the following naming convention / format IMG_20131204_120000.JPG, showing date and time the photo was taken (iPhone/Apple naming convention). However, not all my ...
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245 views

bash script, printing multiple lines that matching to a specific patern

I have a log file and I'm making a script to do some actions. An action is to print a specific area of the log. Every block at the log starts with a specific time stamp and inside the block may have ...
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89 views

Help understanding an egrep expression

I stumbled across the following egrep expression: egrep '^([^aieou]*[aieou]){5,7}[^aieou]*$' /usr/share/dict/words on this page: http://matt.might.net/articles/sculpting-text The expression is ...
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868 views

Rename file in Mac OS Terminal using Regex

Hundreds of images need to be renamed with a terminal command using regex on MacOS 10.9 Mavericks. The files are named this way: 0045AW489R3T(IPCAM)_0_20131124101245_931.jpg ...
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grep: regex only for match anything between parenthesis

How do I match word only between parenthesis Input : this is (test.com) Desire Output : test.com
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“grep: Unmatched [” error when using regex

I'm trying to find a pattern similar to this: tail -n 100000 gateway.log | grep -B10 -A10 'Nov 22 11:13:56 Received Packet from [10.50.98.68' Where "11:13:56" could be any time. This is what I ...
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171 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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Extracting just a single group from a regular expression

I am trying to get a list of numbers from some hacked-together log files using zgrep. So, I am using: zgrep -ie "total time: .* ms" * This returns the whole line that I care about. I'd just like ...
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158 views

Ensure /etc/export contains rule using bash

What's a working example of modifying /etc/export using bash? Example: I want to ensure the following rule is present and valid: /export/home 2400:123::/32(rw,no_root_squash) And it should: Add ...
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Why two almost idetical grep commands return different output: w/o and with filename

I have 2 almost identical greps: [Alex@localhost tmp]$ grep /bin/bash /etc/passwd root:x:0:0:root:/root:/bin/bash AlexL:x:500:500::/home/AlexL:/bin/bash user1:x:501:501:user1 ...
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378 views

Print some fields of /etc/passwd

I have a question concerning the usage of wild cards in Linux. Here I have some lines from a long list of lines in the /etc/passwd -file. root:x:0:0:root:/root:/bin/bash ...
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What does this regex mean?

I was working on the conversion of Unix newline to Windows newline. I tried to unix2dos but it gave me some binary error, so I looked it up and stumbled upon this regex sed 's/$'"/`echo \\\r`/" ...
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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 ...
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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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a string representation using regex (modified)

I would like to use regular expression to represent a pattern with the following type of characteristics 1) It includes a continuous sequence of digit values. The length of this sequence it at least ...
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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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Why doesn't this regex work?

I want to look at the output of git status -s to determine whether there are any untracked files in the tree. I tried the following test, but the regex doesn't match. Why not? $ git status -s ## ...
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156 views

Trouble getting regex to work with find

I'm having a lot of trouble getting find to work with regex flags. Im using egrep on its own to find a date pattern in a file, like this: egrep '[0-9]{4}-[0-9]{2}-[0-9]{2}' which will return dates ...
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lftp exclude syntax confusion

I am confused with the syntax description given for lftp from their website: -x RX, --exclude=RX exclude matching files -X GP, --exclude-glob=GP exclude matching files How ...
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326 views

How to Replace Path in Search field using VIM

I'm trying to replace this text in VIM Actual Path /home/omipenguin/Servers\ Information/systemscript.sh/sysinfo.txt with this new path /home/sysinfo I tried %s/\/home\/omipenguin\/Servers\ ...
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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 ...
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Regular expression in bash script

This is my first time bash scripting so I'm probably making an easy mistake. Basically, I'm trying to write a script that gets the groups of a user, and if they are in a certain group, it will log ...
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578 views

Using a perl compatible regex with GNU grep -P

I'm using this regex (?<=\[')[^,]* on a file containing the following line disk = ['OVS/sdasd/asdasd/asdasd/something.img, w'] I want that to return OVS/sdasd/asdasd/asdasd/something.img How do I ...
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Brace expression does not work in find regex

I have two folders, CA01 and CA02 under current folder, foo: foo -+ | +-CA01 | +-CA02 When I type find . -regex ".*CA[0-9]+" -exec echo {} + Or find . -regex ...
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Why `rename` behaves differently whenever I use full path instead current path?

Ok, I'm answering a question where the OP have several repositories in Ubuntu that might be causing a problem installing unrelated software. I recommend disabling the PPA's using a single liner rename ...
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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 ...
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Regex to find NFS filesystems that aren't being mounted with nosuid, except for ones with special needs

I have a script that runs the command mount -v 2>/some/file, which I then parse with another script using the following regex: ^.*[\ \t]+type[\ \t]+nfs(?![\ \t]+.*\b(?:nosuid|nosetuid)\b).* The ...
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grep + operator

According to the grep manual: * The preceding item will be matched zero or more times. + The preceding item will be matched one or more times. Let's test it echo 'agb' | grep 'a.*b' # returns ...
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How can I reformat tabular data using AWK?

I have a file contain following output. ora.abc.db 1 ONLINE ONLINE serverA Open 2 ONLINE ONLINE serverB Open ora.xyz.db 1 ...
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VIM substitute occurrences of pattern after a particular word in a line

I have such lines in my text. text before pattern = garbage** text after pattern is pattern If in VIM I do %s/pattern/saturn/ it replaces all occurrences of pattern. But I only want to replace ...
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Alternative regex for {}

I am trying to replace all of this line, but the numbers: looktype="123" so only the numbers show up. Is this possible in any easy way? {sub ("look type=\"[0-9]{0,3}", "TEST")} I am trying this ...
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How to match a literal '*' with sed?

I have this line in my file called test.php 'dbs_password' => 'a8b*cyP0', and want to replace into: 'dbs_password' => 'password-here', So I use this sed command with syntax: $ sed -e ...
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Pattern repetition and regexp

Take the pattern [UGLER]* Can the string UUG match against it? I mean to say, is repetition allowed?
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regular expressions with grep

I have this command right here: grep -B10 -A10 '14:14:50 {"channels":["/alerts/6979/new"],"data":"New alerts for unit 6979"}' mygateway.log Rather than searching for 14:14:50 I would like the 50 to ...
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Stuck in separating chars into strings in my approach. Found a working approach but can not understand it

I am trying to figure out how to break a string to be on character per line. I.e ahebhaaa to be: a h e b h a a a I tried: $ echo ahebhaaa | sed 's/\(.\)\(.\)/\1\n\2/g' I.e. my ...
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Why do I need to escape regex characters in sed to be interpreted as regex characters?

It seems e.g. cat sed_data.txt | sed 's/\b[0-9]\{3\}\b/NUMBER/g' that I must escape characters to form a regular expression. In this case I had to escape braces in order to be interpreted as a number ...
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4answers
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vim search numbers containing specific number of digits

I need to find specific length numbers in a big document. I tried to use regex for this. For example, If I need to search for numbers with exactly 2 digits, I use /d/d (i.e. /d twice followed by a ...
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sed : Ignore line starting whitespace for match

I want to replace the default listening port of httpd to 9090. I can edit the line in httpd.conf file using below sed -i "/^Listen/c\Listen 9090" /etc/httpd/conf/httpd.conf But the line Listen 80 ...
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grep for an alphanumeric strings of any length with a colon on each side

How would you grep for an alphanumeric strings of 1 to 50 characters (ideally, any length would work too) with a colon on each side – a typical result would be all the lines containing the string ...
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673 views

How to insert both vimscript variable and string into vim search and replace

I've only just found out about Vimscript's existence as of today, so forgive me if this question is more basic than it seems, but I've been struggling to find an answer to this question for the better ...
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Aptitude regex engine

I was trying to lookup the versions of libdb in the debian archives with something like that: $ aptitude search '~S~ndev$(~nlibdb~(\d~|-~)!~v~rnative)' which didn't work as expected so I changed ...
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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= , classs= , marks=. Using grep "name=\|age=\|class=\|marks=" ...