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Is there a way to add multiple patterns to grep?
This option treats the pattern you used as an extended regular expression. The deprecated version of extended grep is egrep. Another option is to add multiple separate patterns to the grep command. To do so, use the -e flag and keep adding the desired number of search patterns:
When to use-V or-I in egrep?
I used the -v argument to perform the “opposite” meaning of a normal egrep command, so strings with these patterns were not shown; and also used the -i argument to perform a case insensitive egrep search here.
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.
What’s the difference between extended Grep and egrep?
The egrep command is an outdated version of extended grep. It does the same function as grep -E. The difference between grep and extended grep is that extended grep includes meta characters that were added later. These characters are the parenthesis (), curly brackets {}, and question mark.
How to search for multiple patterns in a file?
Search Recursively for Multiple Patterns in a File. The grep command searches only in the current directory when you use the asterisk wildcard. To include all subdirectories when searching for multiple patterns, add the -R operator to grep: grep -R ‘warning|error’ /var/log/*.log.
How to grep for more than two words?
To search for more than two words, keep adding them in the same manner. For example, to search for three words, add the desired string of characters followed by a backslash and pipe: Let’s see how the above grep command looks when using grep -E, egrep, and grep -e:
Where can I find the output of grep?
The output will return results from all files the grep command found in the /var/log/ directory and its subdirectories. In this tutorial, you learned how to use grep to search multiple words or string patterns in a file.
Which is the latest way to use grep?
The latest way to use grep is with the -E option. This option treats the pattern you used as an extended regular expression. grep -E ‘pattern1|pattern2’ fileName_or_filePath The deprecated version of extended grep is egrep.
What is the name of the grep command?
Grep is a powerful utility available by default on UNIX-based systems. The name stands for Global Regular Expression Print. By using the grep command, you can customize how the tool searches for a pattern or multiple patterns in this case.
How to feed results of date command into grep?
In bash, just use something like alertcommand | grep $(date +”%m/%d”) $()executes a command in a subshell and returns the output of the command as string. Alternatively you can enclose the command with backticks to the same effect.