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# Display the current shell
echo $SHELL
# /bin/bash

# Display the Bash version
bash --version

# Show command history
history
history 20           # Show last 20 entries
!42                  # Re-run command number 42
!!                   # Re-run the last command
!ls                  # Re-run the last command starting with 'ls'

# Useful keyboard shortcuts (reference)
# Ctrl+C  — interrupt / cancel current process
# Ctrl+Z  — suspend current process (resume with fg)
# Ctrl+D  — send EOF / logout
# Ctrl+L  — clear the screen
# Ctrl+A  — move cursor to beginning of line
# Ctrl+E  — move cursor to end of line
# Ctrl+R  — reverse search through history
# Tab     — autocomplete command or filename
# Alt+.   — insert last argument of previous command

# Get help for a command
man ls               # Open manual page for ls
ls --help            # Short inline help
info bash            # Detailed info pages

# Identify where a command lives
which bash
# /bin/bash
type ls
# ls is aliased to `ls --color=auto`