ls is the "list" command, which lists files in the working directory.

ls          # show me the files in my current directory
ls /tmp     # show me the files in the '/tmp' directory

echo $HOME  # show me the value of the `HOME` variable
ls $HOME    # show me the files in the $HOME directory

echo 'arg with spaces' 'second arg'
echo "\$HOME is interpolated to: $HOME"

find .         \
  -name '*.rs' \
  -type f      \
  -not -path './target/*' |
xargs grep '"Error\b'

# with ripgrep
rg -Fw '"Error'