Linux bash内置命令集

man cd  -->查询不到，所以会提示bash的内置命令

 . 
 alias
 bg
 bind
 break
 builtin
 caller
 cd
 command
 compgen
 complete
 compopt
 continue
 declare
 dirs
 disown
 echo
 enable
 eval
 exec
 exit
 export
 false
 fc
 fg
 getopts
 hash
 help
 history
 jobs
 kill
 let
 local
 logout
 mapfile
 popd
 printf
 pushd
 pwd
 read
 readonly
 return
 set
 shift
 shopt
 source
 suspend
 test
 times
 trap
 true
 type
 typeset
 ulimit
 umask
 unalias
 unset
 wait  -  bash  built-in commands
 see bash(1)