Question

What Shell command do you use to search for strings matching a regular expression?

a) `grep`
b) `find`
c) `awk`
d) `sed`

Answer 1

The correct Shell command to search for strings matching a regular expression is 'grep'. This command is specifically designed for pattern matching in text data within files or input passed to it. Commands like 'find', 'awk', and 'sed' serve different purposes in text processing and file management.

Step-by-step explanation:

The Shell command you would use to search for strings matching a regular expression is grep. The command grep, which stands for global regular expression print, is a powerful utility available on UNIX and UNIX-like operating systems for searching text using patterns. When using grep, you can specify the pattern (regular expression) that you are searching for, and grep will return all lines from the input that match the pattern.

Here is an example of how to use grep:
grep 'pattern' filename
This command will search for the specified 'pattern' within the file named 'filename' and print each line to the screen that contains a match.

While grep is used for pattern matching, other shell commands such as find is used for searching files in a directory hierarchy, awk is utilized for pattern scanning and processing, and sed is designed for stream editing.