In Previous Years Questions
- In Linux, filter commands are powerful tools that process text data and extract specific information.
- They take input from standard input (stdin) and produce output to standard output (stdout).
- By combining multiple filters, you can perform complex tasks on text data.
Some of the most common filter commands in Linux:
1. cat
- Displays the contents of a file line by line.
- Useful for viewing the contents of small files.
2. cut
- Extracts specific columns or characters from a file.
- Useful for processing data files with a specific format.
3. wc
- Counts the number of lines, words, and bytes in a file.
- Useful for getting quick statistics about a file’s size and content.
4. sort
- Sorts lines of text alphabetically by default.
- Offers various options to control the sorting order and criteria.
5. tee
- Sends the output of a command to both the terminal and a file.
- Useful for recording the output of a command while also viewing it on the screen.
6. tr
- Translates characters from one set to another.
- Useful for converting text to uppercase or lowercase, removing specific characters, etc.
7. uniq
- Removes duplicate lines from a file.
- Useful for cleaning up data and ensuring unique entries.
8. head
- Displays the first n lines of a file.
- Useful for checking the beginning of a file or getting a quick overview of its contents.
9. tail
- Displays the last n lines of a file.
- Useful for checking the end of a file or monitoring log files.
10. comm
- Compares two sorted files and shows lines that are present in one file but not the other.
- Useful for identifying differences between two versions of a file.