15 Less, Grep, and Pipe

Viewing Large Files with less
- less <filename> opens a file for scrolling through long outputs.
- Arrow keys navigate up and down, q exits.
- Useful in non-GUI environments where scrolling is limited.
Piping Output to less
- command | less redirects command output to less for easier reading.
- Works with commands like ls, cat, and grep.
- Prevents overflowing output from scrolling off the screen.
Using grep to Search in Files
- grep <word> <file> finds lines containing a specific term.
- grep sandbox /etc/group filters for "sandbox" in the group file.
- sudo grep sandbox /etc/shadow searches privileged files.
Piping Output to grep
- command | grep <word> filters command output in real-time.
- Example: cat /etc/passwd | grep sandbox finds "sandbox" user details.
- Works with any command generating text output.
Redirecting Output to a File
- command > file.txt saves output to a file, overwriting existing content.
- command >> file.txt appends output instead of overwriting.
- Example: grep sandbox /etc/group > sandbox_groups.txt saves filtered results.
Combining Commands for Efficiency
- Commands can be chained using pipes (|) to filter and process data.
- Example: ls /etc | grep conf | less finds config files and scrolls through them.
- Efficient command usage improves data management and security.