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

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Can I use Find and Grep in one line

I am a complete novice in UNIX and desperately need some help. I have a directory structure based on events. In these events I have one type of file which does or does not contain a pattern for ...
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4answers
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Replace a string containing newline characters

With the bash shell, in a file with rows like the following ones first "line" <second>line and so on I would like to replace one or more occurrences of "line"\n<second> with other ...
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4answers
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Finding the ID of a process and killing it

When ever I need to kill a background process I do ps -e | grep <process_name> Which prints something like this 1766 ? 00:00:13 conky , Then I use the process ID to kill it like so kill 1766 . ...
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2answers
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grep surrounding characters of a match

I'm looking to do a find and replace within a giant database dump, and it's not doing what I think should happen. I'd like to grep for my target string in the file, and then see the surrounding 8 ...
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5answers
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Recursively search folder but exclude svn subfolder

I want to find all occurences of foo in a large file system maintained by SVN but I don't want to match anything contained in any .svn directory. I get immediate matches when I do grep -l -e 'foo' * ...
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Pipe find into grep -v

I'm trying to find all files that are of a certain type and do not contain a certain string. I am trying to go about it by piping find to grep -v example: find -type f -name '*.java' | xargs grep -v ...
6
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1answer
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inexact text search

Is there any utility like grep or even uniq but for inexact search or I should write it myself? I mean it will look at 90% (number may vary) matching, or smth like that. For example I have file with ...
6
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6answers
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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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2answers
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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 ...
6
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3answers
570 views

Print unmatched patterns, using grep with patterns from file

patterns.txt: "BananaOpinion" "ExitWarning" "SomeMessage" "Help" "Introduction" "MessageToUser" Strings.xml <string name="Introduction">One day there was an apple that went to the ...
6
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4answers
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How to add a carriage return before every newline?

I have a file that only uses \n for new lines, but I need it to have \r\n for each new line. How can I do this? For example, I solved it in Vim using :%s/\n/\r\n/g, but I would like to use a script ...
6
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6answers
552 views

Check if a variable contains only what I want, and nothing else

I'm writing a script to build a software from sources, and there's a --platforms option. I would like to allow the user to select multiple items, but I don't know how to prevent them from making a ...
6
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2answers
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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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1answer
848 views

How to detect and delete lines containing ˆ@

I have a simple problem: In my file, the are lines containing the string ˆ@ˆ@ˆ@ˆ@ˆ@ˆ@. I just want to delete all lines with this string, using for example the sed or grep commands. And I would like ...
6
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5answers
12k views

Remove multiple lines after a pattern match but only after pattern match

I am trying to remove all instances of a pattern match from a file if it matches a pattern. If there is a match, the (complete) line with the matching pattern and the next line get removed. The next ...
6
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1answer
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find words with all vowels in order from a file

I have a large dictionary file with 300,000+ words in it and I'm trying to find all words with the vowels aeiou in that order and have only exactly 5 vowels. My current attempt does not seem to be ...
6
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1answer
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Why do I have to escape a “dot” twice?

I know that we can escape a special character like *(){}$ with \ so as to be considered literals. For example \* or \$ But in case of . I have to do it twice, like \\. otherwise it is considered ...
6
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3answers
328 views

Empty a file without grep subsequently treating it like a binary file

Currently I have netcat piping output to tee which is writing to output.txt with nc -l -k -p 9100 | tee output.txt I want to monitor this output, so I'm watching it with tail -f | egrep -i 'regex' ...
6
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2answers
280 views

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 ...
6
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3answers
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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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2answers
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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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5answers
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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 ...
6
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1answer
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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 ...
6
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2answers
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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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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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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 ...
6
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1answer
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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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1answer
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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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3answers
258 views

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 ...
6
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4answers
644 views

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 ...
6
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4answers
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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 ...
6
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1answer
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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 ...
6
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1answer
310 views

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 ...
6
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1answer
193 views

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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2answers
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Grep: search and replace full line

The command grep "foo" myfile.txt prints all matching lines in my file. Now I want to replace the full line with another string. How can I do that?
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2answers
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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 ...
6
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2answers
2k views

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 ...
6
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2answers
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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, ...
6
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1answer
789 views

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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8answers
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How do I delete the first n lines and last line of a file using shell commands?

I have a file named Element_query containing the result of a query : SQL> select count (*) from element; [Output of the query which I want to keep in my file] SQL> spool off; I want to ...
5
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3answers
372 views

Why does this one-liner fail to produce output? [duplicate]

The following produces nothing in bash: while true ; do upower -d ; sleep 1 ; done | grep percentage | uniq I've discovered that it doesn't matter what the last- or even the second to last- program ...
5
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5answers
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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 ...
5
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2answers
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grep on a variable

Lets say I have a variable line="This is where we select from a table." now I want to grep how many times does select occur in the sentence. grep -ci "select" $line I tried that, but it did not ...
5
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3answers
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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 ...
5
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4answers
531 views

extract lines according to a particular column

I have a CSV file like CK,ck XYZ,xyz,xyzs ABC,abc,abcs PQR,pqr,pqrs LMN,lmn, IJK,ijk, I have to check if something is written in column 3 except whitespace, then display the whole line.the output ...
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4answers
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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 ...
5
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2answers
357 views

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.
5
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2answers
358 views

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 ...
5
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3answers
168 views

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. ...
5
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3answers
735 views

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\>' ...