bash and its features
- bash is essentially an executable program — a user’s working environment.
- Under each shell you can open another shell; the newly opened shell can be called a subshell, and each shell is independent of the others.
- You can use the
pstreecommand to view the number of subshells under the current shell.
1. The most important: auto-completion
| Command | Description |
|---|---|
| Tab | Auto-completion |
2. Editing and navigation
| Command | Description |
|---|---|
| Ctrl + A | Jump to the beginning of the current line |
| Ctrl + E | Jump to the end of the current line |
| Alt + F | Move the cursor forward one word on the current line |
| Alt + B | Move the cursor backward one word on the current line |
| Ctrl + W | Delete the word before the current cursor |
| Ctrl + K | Delete the content after the current cursor |
| Ctrl + U | Clear the entire line |
| Ctrl + L | Clear the screen, similar to the clear command |
| Ctrl + H | Backspace, similar to the backspace key |
| Ctrl + T | Swap the two characters before the current cursor |
| Esc + T | Swap the two words before the current cursor |
Ctrl + W and Ctrl + U are quite commonly used. Typos are a very common occurrence.
Ctrl + L goes without saying.
3. Process-related
| Command | Description |
|---|---|
| Ctrl + C | Terminate the current process |
| Ctrl + Z | Suspend the current process in the background |
| Ctrl + D | Exit the current Shell, similar to the exit command |
Ctrl + C sends the SIGINT signal to the currently running process, terminating it.
SIGINT - This signal is the same as pressing ctrl-c. On some systems, “delete” + “break” sends the same signal to the process. The process is interrupted and stopped. However, the process can ignore this signal.
Ctrl + Z doesn’t end the process; it suspends it in the background. You can later resume it with the fg command. The corresponding signal is SIGTSTP.
3. Searching commands you’ve used (highly recommended)
| Command | Description |
|---|---|
| Ctrl + R | Used to search for previously used commands |
I often use history to view command history, but there’s already a ready-made shortcut for it.
After pressing Ctrl + R, type the keyword to search for; if it’s not the one you want, keep pressing Ctrl + R to iterate through the matches.
This command actually queries through the history records as well. If you don’t like this approach, you can just do history | grep xxx, which works just as well.
Summary
These commands noticeably improve work efficiency and need to be reviewed and memorized repeatedly. At the end of this post, I’d like to recommend Linux公社 (LinuxFans), a Linux community with a sense of history and humanism, from which I’ve learned quite a lot.