Comments on: 15 Practical Grep Command Examples In Linux / UNIX

By: edward

edward — Tue, 31 Jan 2012 08:20:30 +0000

For example my data is (file.ave) :

MRR 120101000000 UTC+07 AVE 60 STF 150 ASL
H 150 300 450 600 750 900
TF 0.0149 0.0515 0.1171
F00 -67.04
F01 -69.27

I use grep as:
grep -r ‘MRR’ *.ave > time_0101.txt. In this case all file goes to time_0101.txt, I have many files and I need each output goes to specific file name. Any idea ? And how to use grep to take F00 and F01 ? If I use grep -r ‘F’ *.ave, the first line will be taken also because of STF, Thanks for help..

By: gotham

gotham — Sun, 22 Jan 2012 10:32:39 +0000

awesome. thanks a lot.

By: haydarekarrar

haydarekarrar — Fri, 23 Dec 2011 10:29:49 +0000

Just a minor thing the last result line is removed in the example above, this should be the result:

$ grep “this” greptest.txt
this line is the 1st lower case line in this file.
Two lines above this line is empty.
And this is the last line.

By: 7 Linux Grep OR, Grep AND, Grep NOT Operator Examples

7 Linux Grep OR, Grep AND, Grep NOT Operator Examples — Fri, 21 Oct 2011 06:05:54 +0000

[...] You already knew that grep is extremely powerful based on these grep command examples. [...]

By: Dinesh

Dinesh — Thu, 22 Sep 2011 18:45:45 +0000

Shyam

grep “[^A-Z]” file.txt

Grep will print the lines that does not start with CAPTIAL LETTERS.

Using ^ inside the [] will do the work opposite to the pattern what you have been searching for …

By: Dinesh

Dinesh — Thu, 22 Sep 2011 18:43:19 +0000

Paul

grep \# input*.txt | awk ‘{print $4}’ | sort | uniq > output.txt

Since # is a special character,we are treating # as # by putting backslash infront of that.
Noe Greap searches for pattern # in a list of file starting as input and nding a txt and then awk prints the 4th field and sort is doing sorting the 4th field returns from awk and unis is doing uniq operation.

By: sudheer

sudheer — Sun, 11 Sep 2011 02:32:30 +0000

1) Use grep (or awk) to output all lines in a given file which contain employee ID numbers. Assume that each employee ID number consists of 1-4 digits followed by two letters: the first is either a W or a S and the second is either a C or a T. ID numbers never start with 0s. Further assume that an employee ID is always proceeded by some type of white space – tab, blank, new line etc. However, there might be characters after it, for example punctuation.
What to turn in: Turn in three things:

a. A file with the regular expression which can directly be used by grep (or awk)

b. A text file which you used to test your regular expression. Make sure that you include valid and ‘invalid’ employee IDs, have them at the beginning and the end of lines, sentences, etc.

c. A second document which re-writes the regular expression in a more human-readable form and explains the purpose of the different components of the regular expression. Also include a short explanation of your test cases.

2) Use grep (or awk) to output all the lines in a given file which contain a decimal number (e.g. a number which includes a decimal point). Decimal numbers do not have leading zeros but they might have trailing zeros. Assume the number is always surrounded by white space.

What to turn in: The same three things as above (except, of course, for this problem).

3) Write a regular expression for the valid identifiers in Java. You are allowed to use ‘shortcuts’, but need to make sure that you specify exactly what they are (e.g. if you use digit specify that that means 0, 1, 2, 3, ….9.)

By: 20 Linux Log Files that are Located under /var/log Directory

20 Linux Log Files that are Located under /var/log Directory — Mon, 01 Aug 2011 06:03:51 +0000

[...] what you are looking for in a log file, you can quickly use grep command to grep a pattern. The 15 practical grep examples will take out all your excuses of not using [...]

By: shivaraj Patil

shivaraj Patil — Mon, 25 Jul 2011 17:14:33 +0000

HI i have a file with this values
100 first line
101 second line
101
102
102
109
now i need a script that can take two lines and find which is greatest

By: shyam

shyam — Mon, 30 May 2011 04:45:10 +0000

i have a doubt here i tried to look at output of cmd

grep “[^A-Z]” file.txt

this is showing all characters excluding capital letter
what does this command actually do