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

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3
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1answer
104 views

What is the purpose of those special characters in the sed command?

I found this bash command that creates a directory tree in your console window. I find it quite useful, but I don't really understand how all of the special characters work. Could someone help break ...
0
votes
1answer
81 views

grep: input file 'X' is also the output

I use ubuntu 14.4, and attempt to redirect the output of grep command to a file, but I keep getting this error: grep: input file 'X' is also the output I've searched for this issue and just found ...
1
vote
1answer
39 views

tcpdump won't capture entire packet

I'm using sudo tcpdump -A -s0 -ien0 port 80 | grep schemas-microsoft >> ~/Downloads/convert.txt to capture microsoft-schema xmls being sent throught the internet, when tcpdump is supposed to ...
0
votes
1answer
30 views

Manipulate lynx --dump output to get only specific sections

I'm trying to write a unit that will get me a word's definition from wordnik.com from CLI. Currently my code is: function wordnik { (( $+commands[lynx] )) || return 1 ...
4
votes
2answers
904 views

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 ...
2
votes
3answers
169 views

Using grep/awk/sed to sort and combine 2 files

Ok I am running into a problem. I am taking a wifi log that has MAC addresses listed in it. I want to find out what MAC vendors/manufactors for the devices that are connected to my router. I have 2 ...
2
votes
2answers
249 views

How can I grep a certain text and display its line and the line after as well

I have a file similar to: abcdef 123 ghiflk 234 sfhskdhf 483 I would like to search for a string, and the output should include the next (and/or previous) line as well. So for example: grep "bcd" ...
1
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0answers
25 views

Command that can find files that are not referenced by other files and then delete them

I was wondering if anyone knew how I could go about writing a grep command that recursively finds files that are not being referenced/used in a specific file and/or a directory of files, and then ...
1
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0answers
30 views

grep not matching patterns in scripted session [closed]

We have a bunch of reports that run on a Linux server and I am trying to automate checking them and bringing back relevant parts using Powershell. I'm using a module called SSH-Sessions to connect to ...
3
votes
2answers
285 views

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
votes
4answers
272 views

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 ...
9
votes
11answers
9k views

How can I “cat” a file and remove commented lines?

I'd like to know if there is a way that I could cat file like php.ini and remove all lines starting with ; For example, if the file contained this: ; - Show all errors, except for notices ; ...
2
votes
2answers
114 views

Limit grep context to N characters on line

I have to grep through some JSON files in which the line lengths exceed a few thousand characters. How can I limit grep to display context up to N characters to the left and right of the match? Any ...
1
vote
0answers
46 views

In adb logcat | grep, how to get the entire original line? [closed]

I am using grep on the Android Logcat to only watch the lines related to my application. My command line is like: adb logcat | grep 'MyAppName' But the results I get is not the original logcat ...
3
votes
1answer
153 views

grep not working in a for loop over a list

I have some log files. And I have a list of user ids. My log files are in a particular format log-yyyy-mm-dd e.g. log-2014-09-30 I am trying to search each userId in the log file. This is what I am ...
1
vote
1answer
33 views

grep *gcc* doesn't match anything

I'm using the following code $ rpm -qa | grep -i gcc libgcc-4.8.3-7.fc20.i686 gcc-c++-4.8.3-7.fc20.x86_64 gcc-4.8.3-7.fc20.x86_64 libgcc-4.8.3-7.fc20.x86_64 $ rpm -qa | grep -i *gcc* $ I would ...
1
vote
2answers
80 views

Print a line in stdout that matches an expression if the output contains another expression

This might be a common/easy task but I couldn't figure out from examples on the web or manuals of awk/sed/grep. So, here is the scenario: There is an internal command line tool that prints out a ...
2
votes
2answers
40 views

grep command to display only the two words searched for separated by a comma?

Say I have a file with the following text: Hello there, How are you? How can I grep for Hello and are such that the output of grep looks like: Hello,are
7
votes
3answers
244 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' ...
3
votes
3answers
195 views

Looking to grep or egrep year ranges from 1965-1996

I have a grep that works for some of the dates but having trouble getting my brain to make it fully functional. grep 19[6-9][5-6]$ filename it catches a few correctly but I'm looking to grab ...
1
vote
3answers
23 views

Script to search for 3 different users online and print that

I am attempting to create a script where a user can enter 3 different arguments (usernames) to see if they are online. I currently have who | grep "^$1" which will bring up whoever is searched then ...
1
vote
1answer
56 views

Understanding grep and pipes in linux

I came across this post which explains my problem. Suppose there is a file called file.txt which contains "foo World". The answer posted by Tyler explains a lot however I am confused as to how cat ...
0
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0answers
48 views

BC returns syntax error

#!/bin/bash cd ~/simplesim-3.0/benchmarks INSTS=$(grep "sim_num_insn" ./anagram.txt | awk '{print $2}'); IL1_ACCESSES=$(grep "il1.accesses" ./anagram.txt | awk '{print $2}'); IL1_MISSRATE=$(grep ...
2
votes
1answer
41 views

Quotes in commands - grep example

I wanted to know when to use quotes with grep or other tools. For instance the following two command give the same results. [Jhm@localhost /]$ grep Hello ./testfile Hello world [Jhm@localhost /]$ ...
1
vote
2answers
89 views

How to do a grep on remote machine and print out the line which contains those words?

I have few logs files in my machineB under this directory /opt/ptd/Logs/ as shown below - My logs files are pretty big. david@machineB:/opt/ptd/Logs$ ls -lt -rw-r--r-- 1 david david 49651720 Oct 11 ...
3
votes
2answers
81 views

ack/grep search and sort by modification date

Is there any way to have ack sort the results found by date of modification? (ideally showing the date next to the result?). It doesn't look like ack has a date option, but just in case. If this ...
5
votes
7answers
8k views

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 ...
3
votes
3answers
488 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 ...
1
vote
3answers
163 views

keep only certain part of a string in a certain column

I have a file like this: id target_id length eff_length 1 intron_FBgn0000721:20_FBgn0000721:18 1136 243.944268 1 intron_FBgn0000721:19_FBgn0000721:18 1122 ...
0
votes
2answers
48 views

Regex to grep filler followed by signed float

I want to extract the last column from lines that look like: 880.952 NAV_Y uSimMarine -146.17516 The number isn't always negative, and isn't a fixed length (i.e. doesn't ...
0
votes
3answers
48 views

Filter names from textfile

I have a file where there are names sitting in the first character position. I am trying to find a way to grep all the names. Example here I would want the names BUBBA and SUSAN listed. BUBBA = ...
12
votes
9answers
2k views

How to perform a multi line grep

How would you perform a grep for text that appears on two lines? For example: pbsnodes is a command I use that returns the utilization of a linux cluster root$ pbsnodes node1 state = free ...
3
votes
1answer
1k views

How to grep top most frequent error messages in a unix logfile

If I have a file example apache log file How to extract the top most frequent error messages in a unix log file with no timestamps the key is most frequent error message should come on top of the ...
1
vote
1answer
80 views

Regex works in shell but not through Perl script

I'm having trouble executing a Perl script through the Unix shell using Perl's system command. I've had more complex regex commands I had to adjust accordingly to convert from Unix to Perl, and ...
1
vote
2answers
63 views

How to match a number in one file to a name in another file?

Okay, I hope this is the right place to ask. I have 2 files. The first file has 4 fields: class CRN #, Instructor ID #, Class Section #, Number of Students. Example: 0002 T00005 006 15 0004 ...
1
vote
2answers
49 views

Strings not outputting text found using grep

I am looking for certain strings in (Windows) executable files. First I started with grep -a string file as that treats binary files like text files. The problem there is there is no neat output, ...
3
votes
3answers
431 views

How can I open a file that results from grep?

I often grep a bunch of files to find a line, and then grep returns one result. Rather than copying and pasting the filename into a new command, I'd like to be able to open that one result with an ...
0
votes
4answers
75 views

grep for files and open the resultant matches

I'm trying to open all files based on some return values from grep in the command line. I know that I can use the -l option to only return filenames, but I would like to combine this somehow with ...
4
votes
2answers
58 views

How to exchange words in a filename using the shell?

One of my customers is a school. On their file server all projects have a directory with the same naming scheme. <last name>, <first name> <second name>? - <project ...
3
votes
1answer
75 views

GNU Parallel - grepping n lines for m regular expressions

The GNU parallel grepping n lines for m regular expressions example states the following: If the CPU is the limiting factor parallelization should be done on the regexps: cat regexp.txt | ...
1
vote
2answers
86 views

grepping for multiple items

I have about 6 items I need extracted from and LDAP base dump file fullName: uid: email: ... the colon is required for the search, mainly because uid appears in a number of places in the file but ...
1
vote
1answer
82 views

Exclude hidden subdirectories from grep -r

I have a svn local copy, i want to make a search on the string some_string. $ grep some_string * -r lang/en:some_string=Some string lang/.svn/en:some_string=Some string But if a go little further, ...
0
votes
5answers
773 views

bash event not found trying to match and exclude parenthesis in grep

In a very long line I'll summarize with: (foo),(bar,baz(word,right),(end) I want to print only: (bar,baz(word,right To match the second parenthesis, I exclude the word that follows the ...
0
votes
3answers
35 views

How to make a grep which excludes a bunch of pipes?

I want to make a diff of hostnames using grep. I have 2 files. One yaml and one .pp. In the yaml I have domain names with ips and in the .pp file I have fqdn and ip in hash style. Like this: In the ...
2
votes
1answer
117 views

grep search expression and rename file

I have readable pdf files that all contain the string VAX followed by eight numbers, like VAX00002885. Now I want to find that expression and rename the corresponding pdf to VAX00002885.pdf (in this ...
2
votes
2answers
97 views

How to get grep exit code but print all lines?

I'd like to check whether a line printed by a command contains an error message, but I'd like to also print all the output from the command (for make logs). Is there some way to get all the output of ...
1
vote
3answers
224 views

“grep” the available space from “df” output

Hello I need to grep the output from df. Sadly awk is not an option (even though its the easy option) here I can only use grep. Filesystem 1K-blocks Used Available Use% Mounted on none ...
0
votes
1answer
80 views

Very basic H/W question using pipe and grep

I have two text files, F1a.txt and F1b.txt, with essentially the same data: the driver's surname and their nationality. For example: Hamilton GBR Alonso SPA I have concatenated these ...
0
votes
1answer
124 views

Using Grep Colour to look in a file, and output with a coloured answer in amongst the file contents

I am currently in the process of writing a program in raspberry pi that will allow me to look inside files and have what I entered displayed in colour I think I need to do something to do with ...
0
votes
5answers
80 views

df -k + how to match the root volume line

please advise how to match the "/" volume from df -k command? I tried the following: [root@machine /]# df -k | grep "/" /dev/vx/dsk/bootdg/rootvol 130926685 71378710 58238709 56% / /devices ...