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

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bash find lines starting with string

I have a bunch of files and I want to find which one contains sequential lines starting with a certain string. For example for the following file : Aaaaaaaaaaaa Baaaaaaaaaaa Cxxxxxxxxx Cyyyyyyyyy ...
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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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generate links of pages with incrementing variable

consider the links http://unix.stackexchange.com/questions/tagged/linux?page=2&sort=newest&pagesize=15 ...
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How do I grep recursively through .gz files?

I am using a script to regularly download my gmail messages that compresses the raw .eml into .gz files. The script creates a folder for each day, and then compresses every message into its own file. ...
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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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Use grep to find all files in a directory with two strings [duplicate]

I am trying to figure out the correct syntax to find two strings, the entire part of each string, anywhere (doesn't have to be near each other) in a file. So any file that has both foo and say the ...
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grep for words of no more than a certain length

I'm looking for a way to grep things like: i log for E M, i 1 f x i 0, I xi 1, 3 1,. simply based on number of characters. Nothing in that hypothetical output is longer than three characters. This ...
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Is there a archive of old man pages? specifically for the features available for grep in early 'ed'

This is just a bit of history rummaging... I'd like to know how different today's grep is to the original implementation, introduced by Ken Thompson in ed. which evolved to ex, which then became vi... ...
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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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grep: Ignoring GREP_OPTIONS to search case-sensitive

I have set GREP_OPTIONS="--ignore-case --color" in ~/.bashrc as I normally want grep to work case-insensitive. However, there are times when I need grep to actually search case-sensitive, but the man ...
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Get files with a name containing a date value less than or equal to a given input date

One of my folders contains files in the following format: 3_20150412104422154033.txt 3_2015041211022775012.txt 3_20150412160410171639.txt 3_20150412160815638933.txt 3_20150413161046573097.txt ...
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How to grep netcat output

I'm trying to grep live text stream from netcat, but it doesn't work for me: netcat localhost 9090 | grep sender returns nothing, but I'm sure that it should. If I redirect the netcat output to a ...
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Suppress 'file truncated' messages when using tail

I'm tailing a log file using tail -f messages.log and this is part of the output: Lorem ipsum dolor sit amet, consectetur adipiscing elit. Fusce eget tellus sit amet odio porttitor rhoncus. Donec ...
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Grep for range of numbers [duplicate]

How would you search a log file for a date range? Log file looks like this: 01/14 00:00:01 INFO: received connect request from 10.10.10.10 I need to condense the log to 10 minutes starting ...
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How can I recursively search directories for a pattern and just print out file names and line numbers

Currently I am using grep as follows: grep -lr <PATTERN> . This gives me the following output, containing a list of all files whose contents (not name) contain : ./path/to/file1 ...
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Conditional grep without quiet option

I always thought the quiet (-q) option had to be used when using grep conditionally. But re-reading the man page it seems like it should work without it. So if you want to print matches and use it in ...
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What is the meaning of this test expression []? [duplicate]

I've seen someone use command: ps -ef | grep [h]ttpd and Output is: apache 25125 31006 0 21:54 ? 00:00:00 /usr/sbin/httpd apache 26869 31006 0 22:04 ? 00:00:00 ...
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How to start multi-threaded grep in terminal?

I have a folder which has 250+ files of 2 GB each. I need to search for a string/pattern in those files and output the result in an output file. I know I can run the following command, but it is too ...
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fastest way to grep jar file for a particular name in it?

I am trying to find all the jars which has spring in its name. I am working with windows and using cygwin to run the linux commands. Does my below command looks right? find . -name "*.jar" -exec jar ...
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how to execute lines coming from a grep result?

I've got a text file with certain installation instructions, and I know I can grep for a unique occurrence in the file. For example, the text file has something like: MYDIR=`find /home/user -name ...
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Peculiar piping grep/head behavior

I'm helping the netadmin here with a perl regex to automate operating on some snapshots from our SAN and our scripts does stuff like this: varinit1=$(iscsiadm -m session | grep rbmsdata1 | head -n1 | ...
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How to run grep on a single column?

I want to grep the output of my ls -l command: -rw-r--r-- 1 root root 1866 Feb 14 07:47 rahmu.file -rw-r--r-- 1 rahmu user 95653 Feb 14 07:47 foo.file -rw-r--r-- 1 rahmu user ...
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Number of files not containing given string

I read the question about how to find out the number of files that contain a certain string. This is possible with grep -l "string" * | wc -l. Is it possible to invert this, finding the number of ...
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Recursive grep for words in a particular file type

I wanted a command line command to search all shell scripts in the filesystem for a particular word, so I asked around at work and got the following solutions: grep word `find / -name \*.sh ...
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Find a string only in a specific file inside subdirectories

Let's say I need to find the function GetTypes() in all C# source file (.cs) the directories/subdirectories. I used grep -rn GetTypes *.cs, but I got an error with grep: *.cs: No such file or ...
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How do you get fgrep to find the literal “--help”?

fgrep --help | fgrep "--help" returns just the whole fgrep --help, how do I return just the lines that have the literal "--help" in them? The quotes don't do anything, nor does \-\-help.
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How to search for text in a file ignoring newlines?

I'd like to search for text that may be split over several lines in a file. A grep that would ignore line breaks and return the matching span of lines. e.g. I would be searching for is an example ...
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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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How can I suppress output from grep, so that it only returns the exit status?

I have the grep command. I'm searching for a keyword from a file, but I don't want to display the match. I just want to know the exit status of the grep.
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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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difference between .* and * in regular Expression

I've a file named "test" that contains linux Unixlinux Linuxunix it's linux l...x now when i use grep '\<l.*x\>' , it matches : linux it's linux l...x but when i use grep '\<l*x\>' ...
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How to grep on source code without catching comments

I search a way to grep on source code without having sometimes false-positive because of comments. For instance if I search on foo on this .c source code : /* * foo has changed [...] and is now a ...
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How to replace m part of Lines with n part of Lines?

I have a file "test" like this: RewiteEngine On RewriteCond %{REMOTE_ADDR} !^192\.168\.1\.7$ [NC] RewriteCond %{REMOTE_ADDR} !^192\.168\.1\.8$ [NC] RewriteCond %{REMOTE_ADDR} ...
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1answer
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grepping foo and bar

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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What params do I pass to grep to return only file names?

I'm trying to use grep to find a specific piece of text in a bunch of files on my web server. No problem, except that it returns way more information than I want! Ideally it would just return a list ...
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How to grep for pipe |

How can I grep for line containing pipe character | or for character >: files content: |this is test where is > this is none now what I need using grep command is grep -iE "<some ...
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Why does grep not work with redirection?

Using the top command with redirection works fine: top > top.log Now I want to use grep to filter a certain line: top | grep "my_program" > top.log But the log file will remain empty. But ...
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1answer
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How can I match the page break character in a regular expression?

Nano calls it ^L, but of course, typing something like $ grep -v "^\^L" file doesn't work. Its unicode codepoint is 000C. How can I match it in a regular expression?
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Run `grep` excluding a file in a specific path

I want to exclude the file ./test/main.cpp from my search. Here's what I'm seeing: $ grep -r pattern --exclude=./test/main.cpp ./test/main.cpp:pattern ./lib/main.cpp:pattern ./src/main.cpp:pattern ...
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grep for multiple regexes, and count the number of occurences

Say, I have a file, and multiple regexes have to be searched in it and the number of matches for each regex has to be counted. Thus, I cannot combine the patterns: grep -Po ...
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Why does a grep reboot the machine?

On a RHEL 6.5 Desktop, if I use: sudo grep -r foo /* my desktop reboots. Q: Why?? How to debug this? It's the third time my Desktop reboots because of this :D
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A shell script to write selected fields to a single line

I have a log file trace.log which prints the time stamp, thread name and Transaction method and transaction ID as below. 2014-01-23 15:50:41,724 [catalina-exec-35] INFO TRANSACTION getConnection ...
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Looking for a Java class in a set of JARs with find, unzip, grep

I was trying to find the JAR containing a Java Class. JARs are in zip format. My first attempt was: $ find -name "*3.0.6.RELEASE.jar" | xargs -l1 unzip -l \ | grep stereotype.Controller ...
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tr complains of “Illegal byte sequence”

I'm brand new to UNIX and I am using Kirk McElhearn's "The Mac OS X Command Line" to teach myself some commands. I am attempting to use tr and grep so that I can search for text strings in a regular ...
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Robustly segmenting a csv file containing noisy data

Say I have a csv file with these columns: timestamp,cpu,memory An example of the shape of the actual data would be this chart: Having the data visualized in this way, it's easy for the human eye ...
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Pattern matching across multiple lines

What is a quick and easy way to validate if the pattern "301 domaname.com 200" is present within BASH when spread across multiple lines of output? I was using something like the following: awk ...
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Find all lines between a line matching a pattern and a line matching another pattern

i want to start grepping from the lines that has "CK" at the end of line and stop grepping when the line has "D" at the end. I tried grep "$CK" "$D" file..txt , but it didnt work. Input: kkkkkkkkkkk ...
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What does \bi\b mean in a grep pattern?

What does this command do? grep "\bi\b" linux.txt What is it searching for?
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Using Modifiers of Perl-compatible Regex (PCRE) in grep

According to grep --help and man grep, we can use the -P option in order to interpret the pattern as a Perl regular expression (PCRE, to be precise), instead of the default POSIX basic regular ...
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How can I keep color codes with grep input?

It I grep something twice: ... | grep foo | grep bar It seems foo is not highlighted. Infact, it seems grep removes colorcodes from its input; Any way to prevent this?