BASH_BUILTINS(1) BASH_BUILTINS(1)
NAME
bash, :, ., [, alias, bg, bind, break, builtin, cd, command, compgen, complete, continue, declare, dirs, disown, echo, enable, eval, exec, exit, export, fc, fg,
getopts, hash, help, history, jobs, kill, let, local, logout, popd, printf, pushd, pwd, read, readonly, return, set, shift, shopt, source, suspend, test, times,
trap, type, typeset, ulimit, umask, unalias, unset, wait - bash built-in commands, see bash(1)
which pwd为/bin/pwd
个人判断:pwd既是内建命令,也是外部命令
$type -a pwd
pwd is a shell builtin
pwd is /bin/pwd |