Bash Builtins, Job Control, and Shell Behavior

type -a ls

# Show whether a name resolves to an alias, builtin, function, or executable.

command -v bash

# Print how a command would be resolved.

help read

# Display builtin help text.

alias ll='ls -lah'

# Create a shell alias.

alias

# Print current aliases.

unalias ll

# Remove a shell alias.

enable -n test

# Disable a builtin so external command resolution can win.

set -o

# Print current shell option settings.

shopt

# Print optional shell behavior toggles.

shopt -s globstar
printf '%s
' **/*.sh

# Enable ** recursive globbing.

shopt -s extglob
printf '%s
' !(*.md)

# Enable advanced glob patterns.

set -f

# Disable glob expansion.

history | tail

# Display recent command history.

fc -s old=new

# Re-run last command after simple substitution.

bind -P | head

# Inspect key bindings handled by readline.

source ~/.bashrc

# Load commands from a file into current shell.

sleep 60 &

# Start a job in background.

jobs -l

# List shell jobs with process IDs.

fg %1

# Resume a job in foreground.

bg %1

# Resume a stopped job in background.

pid=$!
wait "$pid"

# Wait for a specific background process.

disown %1

# Remove a job from shell job table.

kill -TERM %1

# Signal a shell job using jobspec.

trap 'echo interrupted' INT

# Run shell code when Ctrl+C triggers SIGINT.

trap 'status=$?; echo "exiting with $status"' EXIT

# Inspect final exit status on shell exit.

trap -p

# Print current trap handlers.