The VMS command line, accessed via a DECterm, is no easier or harder to use than *nix or DOS. VMS commands are wordy, but can be shortened as long as the shortened form is unambiguous. VMS commands are guarenteed to be unambiguous when reduced to three characters, but some can be reduced further. This is actually a good thing because when you miss the 'y' on the end of 'directory', VMS still knows that you want a directory listing. The following list equates *nix and/or DOS commands to their VMS counterparts. It is not exhaustive, but it ought to be enough to get one started moving about the file system and editing text files.
*nix | VMS | DOS1
-----------------+--------------------------+---------------
pwd | show default | chdir
| sho def | cd
-----------------+--------------------------+---------------
cd temp | set default [.temp] | chdir temp
| set def [.temp] | cd temp
-----------------+--------------------------+---------------
cd ../ | set default [-] | chdir ..
| set def [-] | cd ..
-----------------+--------------------------+---------------
rm temp.txt | delete temp.txt;* | del temp.txt
| del temp.txt;* |
-----------------+--------------------------+---------------
rmdir temp | delete temp.dir;1 | del temp
| del temp.dir;1 |
-----------------+--------------------------+---------------
mkdir temp | create/directory [.temp] | mkdir temp
| cre/dir [.temp] | md temp
| cr/d [.temp] |
-----------------+--------------------------+---------------
ls | directory | dir
| dir |
-----------------+--------------------------+---------------
emacs temp.txt2 | eve temp.txt3 | edit temp.txt4
1 - I actually used the command shell in Windows XP Professional.
2 - I understand that emacs is not the only editor available on a *nix system. It's just my favorite, and I'm the one who made the table.
3 - The same sentiment applies to eve on a VMS system.
4 - The same sentiment does not apply to edit for DOS; I know of no other command line DOS editors.