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

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4
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4answers
193 views

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. ...
2
votes
3answers
380 views

awk, sed, grep, perl… which to print out in this case?

I have this syntax in a file (http response times from analog): <thead><tr><th class="x">seconds</th><th class="R">reqs</th><th ...
1
vote
3answers
701 views

Newbie struggles with grep, sed, awk to filter html

I am a beginner linux user, trying to teach myself how to use linux tools on a cygwin install. I decided to make up a project to try to teach myself the basics of shell scripting and simultaneously ...
6
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5answers
13k views

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 ...
3
votes
4answers
122 views

grep to find “print” not “#print”

In debugging, I use a lot of 'print' and commenting out it with '#print'. How can I use grep to find the line without '#' before 'print'? # print <- not detect #print <- not detect abc # print ...
2
votes
1answer
529 views

Grepping number in a file

I have this command $ cut -f2,3 AIS2F1 | grep [2-9][0-9]* | cut -f1 So my second and third fields are something like this Ben 434 Me 12 you 56 So, I thought that the logic should be to cut ...
4
votes
4answers
934 views

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 ...
-1
votes
1answer
382 views

Search low values in mainframe files

I am working with mainframe files and it seems that the low values (x'00') exists in the records in the file which throws off my import for fixed block. Does anyone know how to eliminate those ...
2
votes
3answers
16k views

How to tell grep to match special character at beginning of each word [duplicate]

I have certain questions regarding grep. Why does the following command match '<Hello'? $ grep -E "\<H" test Hello World <Hello H<ello What needs to be done to match '<Hello' only? ...
2
votes
2answers
662 views

find all cpp files and list only those files with names that match a pattern (regex) does not work

I have a whole repository of files and I am trying to get a list of files that match a certain criteria. For example, let us say that I want to take all the files that have the string foo1 and ...
6
votes
1answer
3k views

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 ...
2
votes
2answers
1k views

Use of quotes in GNU grep regular expressions

I could see that certain patterns in the GNU Grep can be enclosed within brackets and certain others need not be. For example, matching the beginning of a word works only if it is enclosed within ...
1
vote
2answers
421 views

Fast utility that indexes files/directories on centos 6 for faster searching through the filesystem

I need to often search a large directory structure (with 1 G / 13K files of data). find / grep take a lot of time. Is there any utility (or can one make an index of these files) for faster searching.
2
votes
2answers
2k views

Grep for string in first line of all files in directory and descendants [duplicate]

How can I grep for a given string in all files in the current directory, and recursively so, only considering the first line? (the #! line, if present, but only if #! is in the -first- line)?
1
vote
2answers
5k views

How to run grep and show x number of lines before and after the match [duplicate]

grep returns just the line where it matched the regex and often what I want to really see is a few (say 2) lines above and below the matched one. Is there a simple way to achieve it? EDIT: OS: Ubuntu ...
1
vote
2answers
952 views

grep: invalid content of \{\}

Here's the command : grep '\(2\)[[:digit:]]\{\1\}' numbers What I want is to match exactly 2 digits after the digit '2', 3 digits if I change the digit '2' to '3' in my expression, 4 digits if ... ...
0
votes
3answers
259 views

For all files that does not contain a string, prepend a string to the file

I am trying to iterate through a list of html files, check to see if {% load static from staticfiles %} exists in the file and if it does not exists, prepend {% load static from staticfiles %} to it. ...
4
votes
2answers
2k views

Tail -f piped through grep not outputing to file, but outputs to console

I'm using the following command tail -f /mydir/myfile | grep "searchterm" >> outfile Without the -f it works fine, but with the -f, which I need, nothing is written to the file. The ...
12
votes
2answers
3k views

grep: Find all lines that contain Japanese kanjis

In a huge UTF-8 text file, I want to show all lines that contains Japanese kanjis. What grep (or other) expression does this? If I am not mistaken, kanjis are the characters between \u4e00 and ...
2
votes
3answers
631 views

How to make GNU grep the default in FreeBSD?

I'm running FreeBSD 9.1-RELEASE. I've installed GNU grep with portmaster textproc/gnugrep. However the "default" grep for users is still FreeBSD grep. # /usr/local/bin/grep -V /usr/local/bin/grep ...
1
vote
4answers
7k views

Getting a list of users by grepping /etc/passwd

For a homework assignment, I need to use grep to parse /etc/passwd and get a list of all users (their usernames only, nothing else). It should use a pipe, and the results should end up in the allusers ...
6
votes
6answers
51k views

List the files containing a particular word in their text

I would like to list the files recursively and uniquely that contain the given word. Example: Checking for word 'check', I normal do is a grep $ grep check * -R But as there are many occurrence ...
2
votes
2answers
248 views

using grep to show entries that match a pattern and are present at least X times

I have a file that have entries like this among other lines Feb 16 17:30:18 ns1 dovecot: pop3-login: Disconnected (auth failed, 1 attempts in 17 secs): user=<accountin@myserver.com>, ...
3
votes
3answers
70 views

How to separate numerical values from identifiers

I'm currently writing a shell script that seperate values from their identifiers (retrieved from grep). For example, if I grep a certain file I will retrieve the following information: value1 = 1 ...
2
votes
2answers
566 views

Matching two files for similar first line

I have 2 set of files. File one contains ID's ex: 1111 2222 6666 3333 4444 File two contains ID and username: 1873 Neil 1111 Roger 7632 Tim 3333 Oscar 8723 Greg 4444 Roy 6666 Patrick I want to ...
3
votes
8answers
3k views

grepping dotfiles with -R correctly?

From time to time I need to find a culprit in an unknown dotfile and instead of trying to figure out which package is to be blamed (e.g. xfce4 or thunar?) and what is their naming convention (.app vs ...
1
vote
1answer
1k views

Sorting by one column then the

Say i have a output file with following: 010513 08:04 ROUTER1 192.168.1.1 68.130.5.10 HIT(1) 010513 08:04 ROUTER1 172.168.1.1 28.130.5.10 HIT(1) 010513 08:04 ROUTER1 122.168.1.1 ...
3
votes
2answers
7k views

How to use tail -f with grep to show surrounding lines

I would like to see the output in a logfile greped by only one domain but also the following two lines. Example: tail -f /var/log/apache2/modsec_audit.log |grep mydomain.de this shows all lines, ...
3
votes
2answers
589 views

sort a file based on length of the column/row

I need to sort a file based on the number of chars in the first column. I have no idea on how to go about this. (On Linux, so sed/awk/sort is available). An example: .abs is bla bla 12 .abc is bla ...
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vote
2answers
2k views

Parsing string by awk and get only elements without pipes or semi colons

I would like get this string line AUGUSTYN|Stanisław|3589238 without | and : I tried something like that: cat baza|grep "AUGUSTYN" -n|awk -F '|' '{print $1,$2,$3,$4}'` (baza is my file with ...
3
votes
2answers
561 views

Please explain the -f option in pgrep

man pgrep says the following about -f option: -f The pattern is normally only matched against the process name. When -f is set, the full command line is used. What does it ...
2
votes
2answers
4k views

grep multiple strings, count lines, echo output for each string

I have a directory of files that is structured like this: data/directory1/file1.xml data/directory2/file2.xml data/directory3/file3.xml ... There are thousands of sub directories within data/, each ...
3
votes
2answers
2k views

grep only subdirectories matching pattern

I have a directory tree consisting of several thousand subdirectories, but I frequently need to grep only a small subset of those directories. How can I grep only those subdirectories matching a ...
7
votes
2answers
16k views

How to grep lines which does not begin with “#” or “;”?

I want to grep smb.conf and see only lines which are not commented.
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4answers
480 views

How to grep number of occurence of two different words in a file on Linux?

How to grep number of occurrence of two different words e.g. 'register' and 'evn' in a file on Linux ? The output should be like following: registered:20
9
votes
2answers
952 views

“grep -r foo *” vs “grep -r foo .”

When using grep -r you could search in all files with either * or . and it seems to return the same thing but is it really the same? Let's say I search for "foo", then I could write grep -r foo * ...
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2answers
4k views

Meaning of asterisk (*) in grep

[USERNAME@host ~] echo -e 'prdxxx\ndadxxx' | grep "da*xxx" prdxxx dadxxx [USERNAME@host ~] echo $SHELL /bin/bash [USERNAME@host ~] dpkg -l | grep -iw bash ii bash ...
8
votes
4answers
29k views

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?
3
votes
5answers
590 views

Print non-existent files from a pipe input

I have a directory of lots of .PDF and .JPG files. There should be a .JPG file for each .PDF with the same name. I'm trying to use a command to find .PDF files that doesn't have a .JPG file. My ...
4
votes
2answers
1k views

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 ...
12
votes
6answers
2k views

How to find files with 100% NUL characters in their contents?

What is the Linux command-line command that can identify such files? AFAIK the find command (or grep) can only match a specific string inside the text file. But I want to match whole contents, i.e. ...
3
votes
5answers
609 views

Search among the content of a large number of plain text files?

I have a directory with 1,242,276 plain text files on my external hard drive. They are totally unorganized with meaningless numbers as their file names. The reason for that is because they were ...
2
votes
2answers
1k views

extract last match from logfile till end

Using sed, grep, awk, or ruby, what's a simple way to find the last match of a string in a larger log file, and send every line following it (inclusive) to another file? Example: grep -A222 ...
1
vote
1answer
119 views

How can I find all matches of a string in a directory?

Using grep (or some other utility), is it possible to find all matches of a regular expression in a folder (searching the text of each file?) I want to find every match of the regular expression ...
4
votes
2answers
3k views

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 ...
0
votes
1answer
3k views

grep the only first word from output with grep -P

I'm trying to grep username users |grep "^\b\w*\b" -P how to do it with grep?
0
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1answer
111 views

What does this “matching lines means”?

The grep manual says "By default, grep prints the matching lines.". What does this matching lines says. When I tried its prints the whole paragraph containing the pattern.
0
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2answers
228 views

Sample file for grep

Can anyone please point to some good sample files that helps to learn grep. This is for academic use. It should be a large one so that students could understand its importance
1
vote
1answer
286 views

Display words in color

I am looking for a tool which takes a file in input and a word to search. It should display the file with color the words if it corresponds to the search. Like grep --colors but displays all the ...
3
votes
5answers
209 views

grep device name and look for next value :

I have this output from a find command: abc,10.11.13.14,def,1.2.3.4,geh,6.7.54.23 where abc,def and geh are device names and could be of any length and others are IP address belong to devices. ...