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

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6
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3answers
98 views

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
123 views

grep + operator

According to the grep manual: * The preceding item will be matched zero or more times. + The preceding item will be matched one or more times. Let's test it echo 'agb' | grep 'a.*b' # returns ...
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4answers
1k 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 ...
2
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4answers
259 views

Zgrep stop after first match when arguments are passed from xargs

I'm using this command to find patterns in zip files (similar to the one) suggested here http://superuser.com/questions/144926/unix-grep-for-a-string-within-all-gzip-files-in-all-subdirectories find ...
9
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2answers
607 views

Script to quickly test all keyboard keys

I need to check some notebooks for bad keyboard keys, and so I'd like to speed that up as much as possible. I found nothing for this specific task, so my idea is a script that reads the pressed keys ...
2
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2answers
114 views

regular expressions with grep

I have this command right here: grep -B10 -A10 '14:14:50 {"channels":["/alerts/6979/new"],"data":"New alerts for unit 6979"}' mygateway.log Rather than searching for 14:14:50 I would like the 50 to ...
19
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3answers
2k views

grep: memory exhausted

I was doing a very simple search: grep -R Milledgeville ~/Documents And after some time this error appeared: grep: memory exhausted How can I avoid this? I have 10GB of RAM on my system and few ...
3
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5answers
162 views

How to grep, then search and replace on the output?

I have some output from iconv, e.g. $ iconv -l | grep ISO | head -5 CSISO4UNITEDKINGDOM// CSISO10SWEDISH// CSISO11SWEDISHFORNAMES// CSISO14JISC6220RO// CSISO15ITALIAN// durrantm:~ How can I change ...
2
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1answer
76 views

How to grep including single quote in a file

I have this line from file.php: 'user' => '', What would be the appropriate command using grep to query the exact line?
3
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5answers
360 views

How can I concatenate a single column of output into a list?

I'm using: ls /proc | grep -v "^[0-9].*" to get a list of all the files and directories in /proc that don't begin with numbers. The output is a single column list, i.e.: acpi asound buddyinfo bus ...
1
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3answers
269 views

grep for an alphanumeric strings of any length with a colon on each side

How would you grep for an alphanumeric strings of 1 to 50 characters (ideally, any length would work too) with a colon on each side – a typical result would be all the lines containing the string ...
2
votes
2answers
79 views

selecting specific string in a field

I have this file: N104 F1810 N104 F3810 N104 F810 N104 F305 and a script to grep an input. Script: enter input read input cat file | grep $input when I input “810”, I get the ...
7
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5answers
18k views

How to display lines 2-4 after each grep result?

I'm parsing a mailbox file that stores e-mail server reports for unsuccessfully delivered e-mail. I wish to extract bad e-mail addresses, so that I remove them from the system. The log file looks like ...
1
vote
2answers
236 views

How to count the number of words and print the lines that match exactly a given pattern?

I want to count the number of words and print the matched pattern lines which matches exactly with following pattern: abc-ERROR: The input File contains: # abc-ERROR: xyxxkkfgfr # def-Error: ...
3
votes
2answers
218 views

grep filter all lines plus one before each hit

I want to parse some output so I exclude all lines that contain either foo or bar, as well as all lines immediately preceding those lines. For example: echo " 1 some line 2 line to exclude because ...
0
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2answers
97 views

Count lines with alphabet in linux

I have a file with a number of lines in a file filename. I want to count how many lines start with character 'a', with 'b' and so on in one go. What command i should execute.?
2
votes
4answers
455 views

How to use the grep result in command line?

When I use grep to find some text which I need, it will display lines containing a match to the given pattern. For example, # grep -r ".*Linux" * path0/output.txt:I hope you enjoyed working on ...
1
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3answers
3k views

grep piping into sed, replacing inline; but I want sed to print the filename and changed line. Is it possible?

Here's my command (break intentional): grep FOO "/Users/gjtorikian/blah" -l | xargs sed -i '' '/FOO/{s/FOO/BAR/g; w /dev/stdout }' At the high-level: grep for FOO in the blah directory; pipe in ...
10
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5answers
956 views

Using grep or awk

To capture a particular pattern, awk and grep can be used. Why should we use one over the other. How does this work in the background? Which is faster and why? E.g If I had a log file and I wanted ...
2
votes
3answers
234 views

How to grep the last number on a line in a bash script

I have output from the smartctl -a command; one of the lines looks like this: 9 Power_On_Hours 0x0032 100 100 000 Old_age Always - 301 I've placed this into a variable (if that's the correct term) ...
2
votes
3answers
260 views

Command substitution in for loop not working

I want to keep all files not ending with .bat I tried for f in $(ls | egrep -v .bat); do echo $f; done and for f in $(eval ls | egrep -v .bat); do echo $f; done But both approaches yield the ...
10
votes
6answers
4k views

How do I list every file in a directory except those with specified extensions?

Suppose that I have a folder containing .txt, .pdf, and other files. I would like to list the "other" files (i.e., files not having the extensions .txt or .pdf). Do you have any advice on how to do ...
3
votes
2answers
485 views

Optimizing a shell script with long running while loop

I have written a shell script which has to do the following: Capture session commands into one file. Every individual command into separate file. Mail every individual command file content based on ...
2
votes
2answers
91 views

Filtering the result of the find command, so that it returns only directories

Is it possible to get only the results from find that are directory paths? Using find with some option, or using grep or some other utility the results are piped into as a filter? I thought something ...
0
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1answer
79 views

Problem with small bash script

I often run find in my code projects when I make a change somewhere and I have to find where it impacts other pieces of code, so I thought about writing a very small script to make this easier, call ...
1
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2answers
152 views

How can I combine grep with file and extra regex

I have a file of strings in each line. For example: AAAAA BBBBB CCCCC etc I want to check each string one by one whether it exists in a series of files in a specific directory. I ...
4
votes
4answers
843 views

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 ...
3
votes
1answer
249 views

Speed up zgrep on a multi-core computer

I'm running zgrep on a computer with 16 CPUs, but it only takes one CPU to run the task. Can I speed it up, perhaps utilize all 16 cores? P.S The IO is just fine, I could just copy the gzipped file ...
1
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3answers
180 views

Escaping * with Regular Expressions and Grep

I have a file that has unique lines that start with 2 stars (**). However when I run a grep command for grep \*\* fileName I get all of the lines in the file. This is very unusual, and what I ...
2
votes
2answers
238 views

Faster way to find matching patterns from external file grep -f {patternfile} {source} in BASH

In *nix terminal (Bash) os there any other faster way to find a pattern (or excluding them - egrep -v option) than using this: grep -f {patternfile} {source} Using this option is painfully slow for ...
5
votes
4answers
5k 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 ...
1
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2answers
155 views

Print a text file from a line number to another after searching for the lines

I want to print a text file from X line number to Y line number The value of X & Y is determined by searching for a specific line in the text file(in this case the page number) I search for the ...
1
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1answer
82 views

Numbering the output of grep

When we're filtering the output with grep, is there any way we can get line numbered output, like we get with cat -n? I'm not asking for the grep -n option which shows the line number of the match in ...
0
votes
1answer
110 views

Stream grep from subprogram, not tail file

Does a simple one liner exist for grepping continuous output from a program rather than just a file? Now just as an example, I would like to skip lines containing PHPUnit in them. For obvious reasons ...
4
votes
1answer
178 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 ...
2
votes
1answer
375 views

Some UTF-8 characters not being recognized by grep or sed

Trying to determine all characters in a file. The file sample consists of: a eɪ abandon əˈbændən ability əˈbɪləti able ˈeɪbəl able ˈeɪbl abortion əˈbɔrʃən abortion əˈbɔrʃn about əˈbaʊt above əˈbʌv ...
1
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2answers
257 views

Grep a string from file

I have 5 filenames created inside a folder for one operation.The filenames are in the following format. ES_currentdate_currenttime_processid_uniqueid.log I want to read the status from the latest ...
-1
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1answer
526 views

if condition, loop in grep [closed]

Could someone please provide help for me. I tried to start writing a shell script but am getting hung up with this issue. I need to grep commands "adb shell ps" and find in it 3 processes with names: ...
2
votes
3answers
364 views

Grep in couple thousands files

I have directory with cca 26 000 files and I need to grep in all these files. Problem is, that I need it as fast as possible, so it's not ideal to make script where grep will take name of one file ...
2
votes
3answers
988 views

How to find multiple strings in files? [duplicate]

I use the following command to find files with a given string: find /var/www/http -type f | xargs grep -iR "STRING1" But how can I find files which include "STRING1" OR "STRING2" OR "STRING3"? ...
4
votes
5answers
630 views

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 ...
3
votes
1answer
286 views

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,"."); ...
2
votes
2answers
276 views

Web front-end to find/grep/ack

In my lab, we are trying to build a web that allows the user to enter queries for find, ack, grep on a specific directory. The web would return an HTML with a table of a list of clickable files (click ...
4
votes
2answers
132 views

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 ...
3
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3answers
1k views

How do I use tee to redirect to grep

I don't have much experience of using tee, so I hope this is not very basic. After viewing one of the answers to this question I came across a strange beheviour with tee. In order for me to output ...
3
votes
3answers
506 views

How to find first match in multiple files

Is there a way for the find command to search for the first match or occurrence of a string or pattern within each of multiple files? I've been using the usual syntax: find dir -iname '*.ext' -exec ...
1
vote
2answers
109 views

Tell a regex expression to skip the beginning of a line before matching

If I had a string like 45mb ./aaaa/bbbb/cccc/dddd and I use a regex like [^\/]*\/ it will match 45mb ./aaaa/bbbb/cccc/ I only want it to match ./aaaa/bbbb/cccc/ but I can't figure out how to do ...
1
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4answers
217 views

using simple regex quantifier expression in grep

Does anyone know why ls | xargs -n 1 basename | grep -E '[0-9]{1}' does not only show occurrences of a single digit between 0-9? For example if I have: touch 1 touch 22 touch 333 touch test_file ...
1
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1answer
49 views

How to use GNU tools to extract and merge two substrings of the same string?

Suppose I get the following result after doing a grep "emailed" /home/John/logs/2013-07-10.171222-0400EDT.html:I have emailed Mark. Thanks I want to extract the date from this so that my output ...
3
votes
2answers
125 views

How to grep recursively in order of last modified time?

grep -r does a recursive search in all files in a particular directory. However, if I want these files to be read by grep in the order of their last modified time, how do I do that?