grep is a command-line tool for searching text patterns in files

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Can we make grep faster by indexing words in files? [duplicate]

Over a decade ago I imagined an improved version of grep that would use indexes to make recursive searching faster. I never got around to writing it, but I wonder if somebody else did! My original ...
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grep IP addresses in expect script

This is part of code in an expect script, I have a problem with searching IP addresses from a file whose name is in the variable $filename. #!/usr/local/bin/expect -- ###Made by Etihkru#### set ...
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Grep searching for files which are not existing

I wanted to search for the text " Starting kernel" in a directory, so I did this: [root@xilinx petalinux-v2013.10-final]# grep -r "Starting kernel" grep: warning: tools/packagemanager/lib/i686: ...
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How to list backup files missing corresponding real files?

I accidentally deleted some files spread across my home directory, but I do not know exactly which ones were removed. How can I get a list of all backup files missing their corresponding file? (...
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Search for specified keywords in files and copy to a new filename based on the keyword

I'm trying to create an .sh script where if any keyword is found in a file then copy that file to the directory /pathtofolder/keywords/$thefirstkeywordfound (overwrite the file if it already exists). ...
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How to use restricted characters in egrep?

I'm trying to use a regex in egrep on Centos 5.10, based on the one I made from this question on SO. T12345 .{1,100}[\n\r].{1,100}2014.03.04 I can successfully match the regex to the content in my ...
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Is there any drawback to using “grep -E” instead of plain “grep”?

I understand that GNU grep without -E uses basic regex and that grep -E uses extended regex. Is there any harm in using grep -E even for situations that would work with plain grep?
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Compare two text files and find matching lines

I have two files A and B. A looks like this (4 to 6 lines): GAGA CAGA GGGT TATT file B is a really big file with thousands of lines, here is a short example: AAATGTCAAGAGACAGAAATGTCAAGAGGGT ...
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Egrep multiple strings in an XML file

I have a collection of XML files in a standard format that I'd like to search to see if they match two strings. Here is the idea: <ELEMENT1>Dave</ELEMENT> <DON'TCARE1>Blaa</DON'...
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What's the most efficient way to grep for two completely separate things and assign the values to separate variables?

CentOS 6.x I want to take the output from curl, grep for two completely separate strings, and assign their respective values as variables. What is the most efficient way to do this (without writing ...
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how to make alias to make grep command shorter [duplicate]

In my coding, I always do grep -rnIi "abcabc" . --color But, how to make an alias that can let me type only one word with my search string? Is that possible?
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Redirect grep error output to file

I wanted to capture to a file the errors being returned on the command line from grep. For example, grep foo.lookup No such file in directory I want to output that to a log file. This is my shell ...
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How to extract submatches from a string and write those to a file?

I want to parse a string for specific submatches and output those - one submatch per line - into a file. Essentially I would like to extract the value of each href-attribute: $ cat Fin <a href="a....
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Using grep to find first two numbers of IP addresses?

I'm trying to figure out how to use grep to pull out only the first two numbers of an IP address in a list. I've got a routine that is isolating the log entires (from Exim) that I need, now I just ...
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Why pidof and pgrep are behaving differently?

I have a init script in /etc/init.d/myservice for initialize a service like this: ... start() { ... daemon /usr/sbin/myservice ... } stop() { ... pgrep myservice pidof myservice ps -ef ...
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Emacs temp dot hash file don't exist

I use find | xargs grep a lot when working on large source code and when I didn't save a file in Emacs it creates .#SomeFile and grep give error that there's not such file (I'm not including because ...
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How can I use grep to search a file for string combinations?

What I'm trying to do is use grep to search my Apache logs. What I want is to find is every entry from a certain IP address that also has .html or .php in the line. In other words, I want to see what ...
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How to match stream against white-list and black-list?

How can I duplicate a pipe stream (output from another program) so that for every line, I can check whether it matches independent regular expressions (ideally, reuse a grep command with options like -...
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Regex for all 10 letter words, with unique letters

I am trying to write a regex that will display all words that are 10 characters long, and none of the letters are repeating. So far, I have got grep --colour -Eow '(\w{10})' Which is the very ...
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Limiting grep search

Please help! Must use grep for this assignment. Must control grep function to search for a string strictly in a given field (Sadly no delimiters) Search field is characters 12-26. Must check if user ...
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My grep (GNU grep) 2.5.1 does not obey backslash character and special expression

I'm trying to follow a section in The GNU Grep Manual but my expression isn't working. Is it my grep version? Red Hat 5.5. $ rm file $ echo 'hello world' > file $ grep 'hello world' file hello ...
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How to show CPU time for processes via top without 'root' procs

Okay, So I've been attempting this for about three hours now without success. How do you search/display/use the top command (or ps command if it works...) to output a list of all procs, sorted by CPU ...
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grep command giving error

I am using grep to filter out the contents on some patterns(genes in my case). For more info,here is the earlier link. Find pattern from one file listed in another My code(should work) but is not. ...
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Grep files excluding few files names

I have a folder who have files names according to date for one month i.e. AP_20140101.gz, AP_20140102.gz, ... for each day. Here 2014 is year, 01 is month and 01 is date (AP_YYYYMMDD.gz is general ...
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How can I open a file that results from grep?

I often grep a bunch of files to find a line, and then grep returns one result. Rather than copying and pasting the filename into a new command, I'd like to be able to open that one result with an ...
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Find pattern from one file listed in another

I want to find patterns that are listed in one file and find them in other file. The second file has those patterns separated by commas. for e.g. first file F1 has genes ENSG00000187546 ...
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Use Unix tools to look for a definition block in an XML.

I am using an XML that has definitions in this form - <definition name="ticketOpen" extends="ticketUpdate"> <put name="title" value="Open Ticket" /> <put name="mainForm" value=...
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Lynx incremental search

I am trying to run an incremental search using lynx. Imagine a page, for example, an index_of page which contains several folders which also contain other subfolders and files. I want to run lynx in ...
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how do i redirect output from tailf & grep to a file [duplicate]

All I wanted is to grep for specific lines in an ongoing log and re-direct it to some file.. tailf log | grep "some words" Now, I want the above command output to get re-directed to some file in on-...
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What are alternative tools for searching files in full content?

I realized that most of the text related tools I use, grep/egrep/awk/sed are line-oriented. I guess that is a simplified approach to search in files but I was wondering if there is another set of ...
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comparing user given time for log file time

Apologies straight away for bad-styled-question-and-heading.....learning unix and its command these days, m trying to figure out a solution for below scenario : Lets say i have a log file which ...
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Implementation Logic [closed]

I have two files,which is something like this: file1 msgid "New" msgstr "" dsvhuvchvdhcvhc msgid "Old" msgstr "hsvhs" kdnvcjdbvj msgid "Bold" msgstr "" file2 dcbjdsbc msgid "New" msgstr "Alas" ...
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Help on editing a script using grep and sed

First I'm new to unix so excuse my simple question, also be aware that I work on AIX. I have a lot of sql files that contains the following string: ${DB_USERNAME}.${TABLE_NAME} Can anyone please ...
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Display column that has a specific string

Content of a sample file is as follow: AA BB CC DD BB 1 2 3 4 9 5 6 7 8 10 I want to display the whole columns that contain BB and DD. In the real case, I do not know which columns contain ...
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Need to grep for specific lines from ongoing log and save it in some file

So, let me start with the overall outcome that i want to achieve. There is just one log, which will have info on certain devices, that i am upgrading. I use "tailf log" to monitor the log. Now, say,...
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pcregrep fails due to segmentation fault

I am extracting the HTML source of a web page using the below command. curl http://www.linkedin.com/pub/ramesh-venkataraman/63/621/b42 -s | w3m -dump -T text/html > foo.txt The foo.txt has the ...
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extract only the substring after double quotes - grep

I have a file which is as below. <a href="http://firstlink.com" title="title1"> <a href="http://secondlink.com" title="title2"> <a href="http://thirdlink.com" title="title3"> <a ...
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counting multiple patterns in a single pass with grep?

I've written a grep loop to iteratively count DNA trinucleotides within a gzipped DNA fasta file containing DNA sequences e.g. declare -a tri=(AAA AAC AAG AAT CAA .. etc) for i in ${tri[@]} do ...
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How to find the path of a file based on its name?

I am trying to find settings.xml file in my Ubuntu machine. I have no clue where it is, and which directory it is in. I tried using this - ls -R | grep settings.xml But it doesn't show me the ...
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grep to ignore patterns

I am extracting URLs from a website using cURL as below. curl www.somesite.com | grep "<a href=.*title=" > new.txt My new.txt file is as below. <a href="http://website1.com" title="...
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grep command in curl

I am trying to extract some URLs from a web page using cURL command. Initially, I use the cURL command as below. curl www.website.com/ Now, the website contains links to some other websites which ...
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sed or grep to get only the values without numbers

I have a file like below. 1. VMware ESX 2. SCCM 3. Healthcare Information Technology 4. vSphere 5. Citrix Metaframe 6. IT Service Management 7. ITIL 8. Active Directory 9. Project Portfolio ...
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grep to extract substrings in a string

I have an output for a command as below. Heading1 I am one value. I am another value. I am third value. Heading2 I am some value. I am someother value. I am new value. Heading3 ...
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grepping foo and bar [duplicate]

I am looking for a command options for grep to find files with the occurences of foo and bar. Grepping with grep -r -e foo -e bar . shows files which have only foo or only bar and files which ...
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find/grep outputs two lines for each file it finds match

I search my code base to find string patterns and list all the files where the pattern is found but only the file and not the lines on which it is found: find . -name *.java -exec grep -l 'someText' {...
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Restricting grep's --color option to the interactive shell

I have the following variable I want to set to make grep behave a certain way: GREP_OPTIONS=--color=always The problem is, I only want this environment variable to be set on the command line. I don'...
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Using empty line as context “group-separator” for grep

I need grep output with context, in color, and blank lines as group separator. In this question, I learned how to define custom group-separator, and I have constructed my grep command like this: grep ...
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Exclude files that have very long lines of text from grep output

I often run grep commands to find things in my code, but the problem with web projects is that there will often be compressed JavaScript and CSS files which create one huge line of text, so that if a ...
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Grep from the end of a file to the beginning

I have a file with about 30.000.000 lines (Radius Accounting) and I need to find the last match of a given pattern. The command: tac accounting.log | grep $pattern gives what I need, but it's too ...
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How can I “grep” patterns across multiple lines?

It seems I am misusing grep/egrep. I was trying to search for strings in multiple line and could not find a match while I know that what I'm looking for should match. Originally I thought that my ...