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

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What does this command mean?

lines=$(grep '^[^:]\+::' /etc /shadow) What does this whole command mean? What does '^[^:]\+::' mean? if I put if else statement like: if [ "$lines" == "" ]; then Will it display (which is ...
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3answers
50 views

piping with grep

I want to search "C" in the grades column inside the file "input.csv": roll,name,total,rank,grade 001,A B,78,23,C 003,F YZ,100,1,* and what I'm trying is: cut -d"," -f4 input.csv | grep "C" ...
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2answers
38 views

getting a list of all lowercase words in a file

I'm trying to get a list of all lowercase words in a file. This far I've gotten to the point of getting a list with the command line cat filename.txt | tr ' ' \\n | grep -w '[[:lower:]]*' | sort -u | ...
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2answers
64 views

What does “if echo $line | grep -F = &>/dev/null” do?

I'm not sure what the following line does in a bash script: if echo $line | grep -F = &>/dev/null then ... I know &>/dev/null is short for >/dev/null 2>&1, I'm not sure, ...
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2answers
38 views

How to indent grep's output? [duplicate]

I need grep's output to be indented with tabs/spaces. This is the plain, un-indented version: MyCmd | grep "id:" I tried this without success:MyCmd | grep "id:" | echo " "
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2answers
75 views

Grep / awk on multiple files to single output

I have several txt-files containing data, where i use grep to search for a current string of text, and use awk to filter out the variable i need. The string is repeated through the file, so i ...
2
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2answers
40 views

Autocomplete from grep output

How might I more easily use a filename found by grep as an argument to vim: $ grep -r foo * lib/beatles/john.c lib/pantera/phil.c lib/pinkfloyd/roger.c lib/pinkfloyd/richard.c ...
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3answers
1k views

How to pick 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) ...
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4answers
43 views

grep all the lines in a file and write line to a file from the pattern matching point

For example, a temp.txt file contains information like below: adsf on line jhkjhvjdbvjvbvbdjkvn qerwtt on line fdgdgdgdd qwqertg on line safffasffaf wrt on line adaddsd I want to grep for ...
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2answers
13 views

Compare 2nd column of the 1st file and 1st column of the 2nd file and print the matched records of the 1st file

I have two files large files: f1.txt: 5020118359 |13ZJ24001218 |20141224|R 5020120475 |13ZJ38000813 |20141204|R 5020127431 |13ZJ38001569 ...
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1answer
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live tail (tail -f) of file being grepped

i can do tail -f -n20 <file> to see the last 20 lines of the file, live. If i want to grep something, tail -f <file> | grep <pattern>, it will still be live, but will only grep ...
0
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1answer
37 views

grep for numbers over 10

I'm looking through a file for specific kernels. I want everything from 3.8. to 3.17. egrep 3.[8-17] is kind of the thing I want but that obviously doesn't work. How do I grep using the example ...
1
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5answers
263 views

To remove extra space from line using shell command

This is my file, TLRUIDA CBdms Status DP 6/1/1 DC 6/1/5 0 Y TLRUIDA CBdms Status DP 6/2/1 DC 6/2/5 0 Y TLRUIDA CBdms Status ...
1
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1answer
21 views

cshell alias: How to use nested single quotes(') in in cshell alias

I am trying below alias in cshell: alias sll 'ls -l \!* | grep -oE '[^ ]+$' | paste -s | xargs ls -l' For this CSH says, Illegal variable name. If I use \$, alias will be set without any error. ...
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2answers
33 views

How to grep a log file from specific date to end of file?

I am looking to grep an Apache access_log file from a specific date/time to the end of the file, so for example I want to grep from the first match of the following string to the end of the file: ...
2
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3answers
88 views

Searching a keyword in multiple pdf files

I want to search for a specific keyword in multiple pdf file using pdftotext command. Normally we can search inside a single pdf file using the following command: pdftotext file.pdf - | grep keyword ...
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0answers
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Complex sed Command for Insert Command [migrated]

I have a bunch of php files which have many insert commands. In each query i want to insert a coloumn variable admin_id = '$admin_id' i.e. if the query is insert into users (ch_id, num_value) values ...
1
vote
1answer
31 views

Estimate time spent on Git project with grep

Consider a Git log: commit 4d6b30238fbfc972ea4505cadf43abd316506d9e Author: Dotan Cohen <dotancohen@foobar.com> Date: Mon Jan 11 22:41:21 2016 +0200 Final foobar version commit ...
3
votes
1answer
15 views

Searching for specific user group membership with an exact match

A user has multiple group memberships that contain spaces. Example: mydomain\staff mydomain\staff admin mydomain\staff super User groups can be returned using: id -Gn username | grep -i -o ...
0
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1answer
61 views

Using sed instead of grep to output only matching part of line

I am writing simple bash script (actually learning how to do it ) and i want this function to use just echo and sed and return exactly the same output. I found solutions with sed, they worked in ...
0
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1answer
27 views

How to select lines in a file that contain a number from a list of numbers

I have a text file, file.dat, with a number of columns separated by a space. There are some numbers in the second column. I have another text file, select.dat with a list of numbers. I'd like to ...
2
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2answers
40 views

How to append string with dash?

I am trying to append create a string that will be evaluated in the middle of a grep line. It is to find possible occurrences of different usernames within a certain file. However, I do not know how ...
1
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1answer
33 views

grep content between two starting bracket

Below is file output that I want to access [1] RsyncCommand: 0 Number of files: 18 Number of files transferred: 0 Total file size: 24.01M bytes Total transferred file size: 0 bytes Literal data: 0 ...
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0answers
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How to take lines containing a particular string tag from a text file and add then to another text file?

I have a large text file with some data that I need and a lot of data that I don't need. The data that I need has a string tag at the beginning of the line followed by a numerical value which I need. ...
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6answers
181 views

Take grep value and output the count and the value together

I am trying to make a bash script that greps value and output the count and the value together Something like this grep -c 'Thenis' example.txt > example.lst But in that list file not only to ...
5
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1answer
54 views

Behavior of grep -o on OSX

On Linux, when I do echo foo | grep -o '^.' to get the first character, it prints f as expected. (I know, | cut -c1 would probably be faster.) But on OSX, doing the same results in 3 matches (3 ...
4
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1answer
156 views

grep of top output yields funny characters upon redirection to file

I am running CentOS 6 and I am trying to grep the output of top and redirect it to a file. I.e. top -u user1 -n 1 | /bin/grep somecommand &> scratch.txt The output of vim scratch.txt is ...
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1answer
43 views

Fetching logs from log file using grep

I am trying to fetch logs from log file using grep command and format of log file is as follows: [1/10/16 23:55:33:018 PST] 00000057 ServerObj E SECJ0373E: Exception message at ...
0
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2answers
73 views

Parsing HTTP response with shell

I want to parse below HTTP response but I cannot figure out how to grep the values separately using a single curl request. I need these two output. 1. status_code - (Array of HTTP status codes) 2. ...
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3answers
59 views

grep a awk string from a file and write to the other part of string file

My file, aaa,has 5 lines. 01_AAA-11-ID22 02_BBB-33-ID44 03_CCC-55-ID66 . . I tried to grep anything after underline from a file bigfile.txt for i in $(cat aaa) do A= $(awk -F '_' '{print $1}' $i) ...
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5answers
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How to use grep and cut in script to obtain website URLs from an HTML file

I am trying to use grep and cut to extract URLs from an HTML file. The links look like: <a href="http://examplewebsite.com/"> Other websites have .net, .gov, but I assume I could make the cut ...
12
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3answers
71k 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"? ...
2
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2answers
61 views

Selective extraction of data

I have the following block of data in a txt file : Informatica(r) PMCMD, version [9.5.1 HotFix4], build [313.0217], SOLARIS 64-bit Copyright (c) Informatica Corporation 1994 - 2014 All Rights ...
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1answer
26 views

cut command behaving differently when its output is “ * ” [duplicate]

I am trying to create a shell script, below is a part of which where i am trying to extract some value from a record in a file: tgt_val=`cat $file_name | grep "$string_name" | cut -d"|" -f$column_no` ...
10
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3answers
284 views

How to extend bash aliases

How to create an alias that actually extends another alias of the same name in Bash? Why: I used to have GREP_OPTIONS set on .bashrc to something like this: GREP_OPTIONS="-I --exclude=\*~" I also ...
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3answers
3k views

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, ...
3
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1answer
48 views

Colored Output from Bash Script

I'm running grep inside a bash script. If I run the grep command directly, I see colored output of the file name and search string: grep -i username /tmp/sess_* If I put that command in a bash ...
0
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0answers
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Reboot on grep in /sys directory

I just run the following command (on a Android in VirtualBox): grep -Hirn 'VirtualBox' /sys/* and the system rebooted. I wonder why this is the case, any suggestions?
1
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2answers
71 views

Complex sed Command with AND/OR/NOT

I have a bunch of php files which have many select commands. In each query i want to insert a coloumn variable admin_id = '$admin_id' i.e. if the query is select * from users where abc='xyz' and ...
1
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3answers
109 views

regex matching and substring extraction

I have these files, manually created by many different people are coming in. Formatting, although following a certain rule, is not uniform. think of these three lines below ...
56
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4answers
14k views

Convince grep to output all lines, not just those with matches

Say I have the following file: $ cat test test line 1 test line 2 line without the search word another line without it test line 3 with two test words test line 4 By default, grep returns each ...
1
vote
3answers
47 views

remove files based upon diff of two text files

I have created two .txt files that look like: 5fba026dcf271c6fa174b9fc2fc1fefadf1370f9 ./.changeFiles/change/addImage1.change bb352fba5807f4d03ea11abb00e411b00ce38673 ...
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1answer
26 views

Pattern highlighting command [duplicate]

Folks, I want to know if there exists a command that just highlight some portions of the input text, rather than filtering it like grep does. To give an example, suppose the following input text: ...
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0answers
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Can I clear an env var during bash completion?

I use bash completion from https://bash-completion.alioth.debian.org/ and some vendor supplied scripts too (eg. https://github.com/git/git/blob/master/contrib/completion/git-completion.bash) I also ...
29
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3answers
84k views

Can grep return true/false or are there alternative methods

I'm trying to write this script for an assignment - it's only the second one I've written so bear with me. As a part of this script, I need to be able to check if the first argument given matches ...
1
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2answers
35 views

Return line conditonally on next line

I am trying to return a list of IP Addresses for computers that have a windows OS (for my security course). The output is in this format Nmap scan report for 192.168.xx.xxx Host is up (0.066s ...
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4answers
68 views

How to show only hidden directories, and then find hidden files seperately

I'm trying to list all the hidden files in a directory, but not other directories, and I am trying to do this using only ls and grep ls -a | egrep "^\." This is what I have so far, but the problem ...
105
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11answers
37k views

How can I prevent 'grep' from showing up in ps results?

When I search for some process that doesn't exist, e.g. $ ps aux | grep fnord wayne 15745 0.0 0.0 13580 928 pts/6 S+ 03:58 0:00 grep fnord Obviously I ...
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0answers
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How to extract weather data from a html doc using linux string manipulation

I need to extract these info from this weather forecast site, but I don't know how much about string manipulation in linux: acm_RecentLocationsCarousel.push({name:"Irvine, CA", daypart:'day', ...
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4answers
50 views

bash extract a substring from “1.2.3-SNAPSHOT”

How can I substring a 1.2.3 from a 1.2.3-SNAPSHOT from bash? I tried echo '1.2.3-SNAPSHOT' | grep -o "^.*(?=(\-SNAPSHOT$))" but it didn't work Ideally I'd like a command to return 1.2.3 in both ...