Introduction
When working with the command line in Linux, viewing and manipulating file content is a frequent task. Whether you need to display an entire file, paginate through large text files, or sort contents for better readability, the CLI offers powerful utilities.
In this guide, we'll explore essential commands such as cat, more, less, and sort, breaking down their functionalities and practical use cases.
cat – Concatenating and Viewing File Content
The cat command, short for "concatenate," is a simple yet powerful tool for viewing and merging files.
Basic Usage:
cat config.cfg
This displays the full content of config.cfg.
Numbering Lines:
cat -n config.cfg
Using -n adds line numbers to all lines, whereas:
cat -b config.cfg
Only numbers non-empty lines.
Creating a File:
cat > myFile.txt
This creates myFile.txt and allows text input (Ctrl+D to save).
Displaying Hidden Characters:
cat -A config.cfg
This reveals end-of-line markers and tab characters.
more – Viewing Large Files Page by Page
If a file is too large for a single screen, more provides a paginated view.
Basic Usage:
more fileName
This displays content one screen at a time. Press Enter to scroll and q to quit.
less – A More Advanced Pager
Unlike more, less allows bi-directional navigation and searching within a file.
Basic Usage:
less config.cfg
Navigate using arrow keys. Search using /search_term, and quit with q.
Show Line Numbers:
less -N config.cfg
Prevent Line Wrapping:
less -S config.cfg
This ensures long lines remain on one row.
sort – Organizing File Content
Sorting is essential for making data more readable.
Sorting a File:
sort file1.txt
Sorts the file alphabetically.
Reverse Sorting:
sort -r file1.txt
Displays results in reverse order.
Numeric Sorting:
sort -n file1.txt
Sorts numbers correctly (e.g., 1, 2, 10 instead of 1, 10, 2).
Removing Duplicates:
sort -u file1.txt
Eliminates duplicate lines.
Conclusion
Mastering these basic CLI commands enhances productivity when working with files. Whether quickly viewing content with cat, paging through large files with more and less, or sorting data for better organization, these tools are fundamental for any Linux user.
Experiment with different options and combinations to optimize your workflow and unlock the full potential of Linux CLI utilities.