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

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Grepping for a block of text with parts that can be optional

I have multiple entries that describes an event in a very large log file, say A.log. I would like to do two things with the event entries in the log file: Count the number of occurrences of each ...
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148 views

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 use grep/ack with files in arbitrary encoding?

On my Linux desktop I have a UTF-8 locale. When I try to search some KOI8-R encoded files with grep (ack), it fails. If I manually encode the pattern into KOI8-R and pass that as an argument, it ...
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Pattern Matching Exclude Duplicate Characters

Is there a regular expression for the following that matches characters in a character set but only once? In other words, once a character is found, remove it from the set. If grep cannot do this, ...
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Search a pattern and print preceding lines starting with another pattern

I need to grep for a pattern and once I find it, I need to look for another pattern preceding that and print all those lines in between those. Better example: 1 a 2 a 3 a 4 a 5 a 6 b 7 c 8 d 9 xyz ...
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How can I search/browse in some process's memory?

I'm using MacOS X 10.7 and I'm not very familiar with unix. Is there a command for a search in some process's memory for a string?
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grep lines starting with “1” in Ubuntu

I try to search for lines that start with "1" using ls -1 | grep ^1* but it returns lines that do not start with 1. What I am missing here?
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How to exclude some files not matching certain extensions with grep?

I want to output all lines containing the word OK recursively from a directory. But there are a few extensions which I need to exclude from the result: *~ *.map *.js except *.debug.js I tried: ...
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Show lines matching a pattern and the 4 lines before each

For example, from this file: CREATE SYNONYM I801XS07 FOR I8010.I801XT07 * ERROR at line 1: ORA-00955: name is already used by an existing object CREATE SYNONYM I801XS07 FOR ...
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Detecting pattern at the end of a line with grep

If I do: $ ls -R .: 4Shared/ Cloud/ ./4Shared: UFAIZLV2R7.part3.rar ./Cloud: UFAIZLV2R7.part2.rar.part UFAIZLV2R7.part1.rar.part UFAIZLV2R7.part4.rar.part If I want to list the .rar files only, ...
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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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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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How do regular expressions differ from wildcards used to filter files

While we use * to denote zero or more previous characters in grep, we use *.c to find all C files when we use it with the ls command like ls *.c. Could someone tell how the use of * differs in these ...
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make grep output without trailing newline

Please consider this snippet: X=$(grep -m1 'some-pattern' some-file | sed -n 's/.* //p') I want to put last word in a variable if some pattern condition is matched for lines in arbitrary text file ...
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Recursive search doesn't work for grep on solaris

On our Solaris server I'm finding that grep -r doesn't work, which is the usual way that I use grep. It seems that egrep has the same behavior. Given that I have no control over the machine, is there ...
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Using grep -v on multiple arguments

Is there a simpler way to do this? grep -v foo file | grep -v bar There're probably very elegant ways to do it with egrep, but how to go with plain old grep? EDIT: grep -v 'foo\|bar' file seems to ...
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grep for multiple strings in files, and then list the files in the order of size

I am in a folder with lots of .txt file, I would like to find all the files which contain both stringA and stringB (not necessarily on the same line), then list these files in the order of the size ...
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Use command grep and locate

How I can make the grep command locate certain words in the files specified by the routes found by the locate command? locate my.cnf | grep user (I want that grep command search the word "user" ...
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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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Printing lines from one file if part of them appears in another. Both files are millions of lines long

I have two files, let's call them 123.txt and 789.txt. 123.txt is 2.5M lines long, and 789.txt is 65M lines long. Is there any way to use grep or similar to keep any lines from 789.txt that contain ...
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Bash-completion and grep

I installed a program (iftop) on Debian Squeeze but some days ago I forgot it's name. I had only this information about the program: 1) It was called *top 2) I could find it using bash-completions. ...
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Why piping find and grep returns nothing?

I'm trying to have grep search inside specified files that are returned by find: find . -type d -name 'mydir*' -exec find '{}' -name '*.java' \; | grep 'MyClass' This doesn't work. Meanwhile, ...
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Grep 'OR' regex problem

I am trying to use grep with a regex to find lines in a file that match 1 of 2 possible strings. Here is my grep: $ grep "^ID.*(ETS|FBS)" my_file.txt The above grep returns no results. However if I ...
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Print all lines not containing punctuation

I want a regex pattern which can print all lines not containing punctuation : Input : .I am line 1 I am ! line 2 I am line (3) I am line 4 Output: ( should be) I am line 4 What I've tried so ...
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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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Count lines matching pattern and matching previous line

I want to count the number of times that a role is successfully deleted. The problem is that one line of the log file will show that the script is about to delete the role: Prepare to remove role X ...
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What is the python equivalent of grep -v?

I like grep -v. I use it all the time. But I am also doing some text processing in python, and there is one crucial thing that I lack. Usually, I use grep -v to take extraneous stuff out of text. ...
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grep caret appears to have no effect

I was under the impression that a caret symbol means "beginning of the line" with Extended POSIX regular expressions. However, when I use it with grep it behaves unexpectedly. #grep --version GNU ...
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1answer
182 views

Literally grep the only word in a line

I know grep -F can search for literal strings, but I want to do something like while read word; do grep -F "^$word$" FILE; done < wordlist i.e. the words need to be treated literally, at the ...
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How can I grep for a string containing regex metacharacters like $ and '?

I want to search all files in the current directory and below for the substring $form['#node']. So, I have tried, initially: grep -R "\$form\[\\\\'" . and grep -R "\$form\[\'" . But it returns no ...
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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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How to adjust column width in Linux command output

When I used this command on Red Hat Linux /usr/sbin/ss -i I get the following output below: State Recv-Q Send-Q Local Address:Port ...
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How to print all lines after a match up to the end of the file?

Input file1 is: dog 123 4335 cat 13123 23424 deer 2131 213132 bear 2313 21313 I give the match the pattern from in other file ( like dog 123 4335 from file2). I match the pattern of the line ...
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grep second time faster

Suppose I do a time consuming recursive grep search. After seeing the results I want a different output; for example I want to add the option -C 3 for 3 context lines. I can do the whole search again ...
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How can I act on the results of the “locate” command?

I'm trying to find where check_dns is defined in nagios' commands.cfg file, although there are quite a few files. I know I could run something like find / -name "command.cfg" -exec grep check_dns {} ...
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Grep a directory and return list with line numbers

I'm currently trying to learn more about bash scripting and all of that fun stuff, and I pieced together this little command: find $path | xargs grep -n $pattern | awk '{print $1}' While this DOES ...
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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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conditional coloring in grep

I have a simple bash script. One line of my script matches a "pattern" with grep and colors the match grep -i --color=always -- "$1" I need to modify it, so that it only colors the match, if the ...
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To grep 20 characters after and before match

I have the problem that I get too much information after the match for grep -RnisI --color=auto "pseudomonas" * I want to get only like 20 characters or 10 words after and before the match. What ...
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Why does grep sometimes show the file name, sometimes not?

Can somebody please explain to me why I don't get the full path in example 1? example 1 - returning found line grep MODIFY /opt/releases/packages/cr_c_cr6/sas/dbms/*/*; outcome: MODIFY example 2 ...
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shell script to read from multiple files in parallel

I need to write a script that runs parallel and looks for a string in multiple files. I tried a lot of options but they slow down the speed of my processor.
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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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1answer
459 views

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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1answer
308 views

grep: display filename once, then display context with line numbers

Our source code has error codes scattered throughout. Finding them is easy with grep, but I'd like a bash function find_code that I can execute (eg. find_code ####) which will provide output along ...
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Piping search term (not filename) to grep

I want to pick out certain lines containing a given number from a file. The file I want to search is called os_clusters/piRNA_clusters.bed. awk '{if (a[$0]++ == 0) {split($0,b,"."); ...
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how to use grep for specific files?

for example I type ls -altr | grep "23 Dec" so it will show files for 23 Dec only and I want to use grep for them, like ls -altr | grep "23 Dec" | xargs grep -l "some_string" but this doesn't ...
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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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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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recursive search for a pattern, then for each match print out the specific SEQUENCE: line number, file name, and no file contents

What I am after is almost exactly the same as can be found here, but I want the format "line number, separator, filename, newline" in the results, thus displaying the line number at the beginning of ...
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1answer
718 views

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?