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How do you grep more lines?
To also show you the lines before your matches, you can add -B to your grep. The -B 4 tells grep to also show the 4 lines before the match. Alternatively, to show the log lines that match after the keyword, use the -A parameter. In this example, it will tell grep to also show the 2 lines after the match.
How do I limit grep output?
Limit grep Output to a Fixed Number of Lines Limit the number of lines in the grep output by adding the -m option and a number to the command. In this case, the terminal prints the first two matches it finds in the sample file.
How to get output and return value of grep?
The response can be no lines, 1 line, or 2 lines. In case grep returns no lines (grep return code 1), I abort the script; if I get 1 line I invoke A () or B () if more than 1 line. grep’s return code is 0 when the output is 1-2 lines. grep has return value (0 or 1) and output. How can I catch them both ? If I do something like:
Can you use grep to search multiple strings?
You can grep multiple strings in different files and directories. The tool prints all lines that contain the words you specify as a search pattern. In this guide, we will show you how to use grep to search multiple words or string patterns.
How to show lines before and after a match in grep?
You can add some additional parameters to your grep command, to search for keywords or phrases in files, to also show you the files that match before or after your match. This is especially useful if the lines before or after that match are relevant for your search queries. A normal grep looks like this.
When to use Grep and not match multiple patterns?
Using sed command: GREP AND: Match Multiple Patterns. It is also often required to grep a file for multiple patterns – when it is needed to find all the lines in a file, that contain not one, but several patterns. Note, that you can both find the lines in a file that match multiple patterns in the exact order or in the any order.