“ env”和“ set”（在Mac OS X或Linux上）有什么区别？

set

env

env

type -a env set
help set
(set -o posix; set) | nl

declare

compgen

man bash | less -p \'-A action$\'  # info on complete & compgen

# listing names of variables
compgen -A variable | nl       # list names of all shell variables
echo ${!P*}                    # list names of all variables beginning with P

compgen -A export | nl         # list names of exported shell variables
export | nl                    # same, plus always OLDPWD
declare -px | nl               # same

declare -pr                    # list readonly variables

# listing names of functions           
compgen -A function | nl
declare -F | nl
declare -Fx | nl

# show code of specified function
myfunc() { echo \'Hello, world!\'; return 0; }
declare -f myfunc  

set

env

set

set +x

set -v