cd — Change the Current Directory
cd is bash shell’s built-in command. It is used to change the present working Dir to specific Dir.
$ cd -- Change the current Dir to $HOME ($HOME is the default). $ cd ~ -- Same as above. $ cd ~bharathi -- Goto the Home Dir of bharathi. $ cd myprj -- Change the current Dir to myprj. $ cd .. -- Goto the parent Dir. $ cd - -- Goto the last visited Dir.
CDPATH – Easy access to frequently used Dirs. For example, I use /usr/a/dir1, /usr/b/dir2/ and /usr/c/dir3 very frequently. So I added the above dirs CDPATH like this CDPATH=/usr/a/dir1/:/usr/b/dir2/:/usr/c/dir3/ Now there no need for me to type exact path to cd. Just cd dir1 will cd to /usr/a/dir1. Actually cd will looks into CDPATH before doing the action.
1) Before changing to new path, cd will save the old path in the $OLDPWD evn variable.
2) After changing to new path, cd will save the new path in the $PWD env variable.
Read : help cd