Grep huge number of patterns from huge file
I have a file that’s growing about 200,000 lines a day, and it is all formed with blocks of three lines as such:
grep
What is the email matching regex in basic regex for grep?
I created a text file and put some email addresses in it. Then I used grep to find them. Indeed it worked:
Count total number of occurrences using grep
grep -c is useful for finding how many times a string occurs in a file, but it only counts each occurence once per line. How to count multiple occurences per line?
How to search text throughout entire file system?
Assuming that the grep tool should be used, I’d like to search for the text string “800×600” throughout the entire file system.
How to check if any IP address is present in a file using shell scripting?
I have a script that generates some output. I want to check that output for any IP address like
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 this:
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.
How to grep lines between start and end pattern?
I have a file which is having following content: zdk aaa b12 cdn dke kdn Input1: aaa and cdn Output 1: aaa b12 cdn Input 2: zdk and dke Output 2: zdk aaa b12 cdn dke I could use below commands to achieve: grep -a aaa -A2 file # Output 1 grep -a aaa -A4 … Read more
Why does grep not work with redirection?
Using the top command with redirection works fine:
grep doesn’t output until EOF if piped through cat
Given this minimal example