HOME, Home and home in tcsh

[jd1008]

On 06/08/2016 08:56 PM, Polytropon wrote:
> On Thu, 9 Jun 2016 10:29:44 +0800, Erich Dollansky wrote:
>> Hi,
>>
>> the answer to my question might be so obvious, but I do not know it.
>>
>> I use this to set the home for the current project I am working on and
>> then use cd $Home to return to the project's home directory:
>>
>> setenv home "`pwd`/"
>> setenv Home "`pwd`/"
>>
>> 'home' contains always my real home directory. 'Home' contains the
>> project's home directory as expected.
>>
>> Does anybody know why it is like this?
> The variable $home is set by the C shell automatically, similarly
> as it does "set path = (... list of path elements ...)"; $home is
> set like $HOME by the shell itself and should not be altered by
> the user (without purpose). :-)
>
> >From "man csh":
>
>         The character `~' at the beginning of a filename refers to home  direc-
>         tories.   Standing  alone,  i.e., `~', it expands to the invoker's home
>         directory as reflected in the value of the home shell  variable.
>
> [...]
>
>     Special shell variables
>         The  variables  described  in  this section have special meaning to the
>         shell.
>
>         The  shell  sets  addsuffix,  argv,  autologout,  csubstnonl,  command,
>         echo_style,  edit,  gid,  group,  home,  loginsh,  oid,  path,  prompt,
>         prompt2, prompt3, shell, shlvl, tcsh, term, tty, uid, user and  version
>         at  startup;  they do not change thereafter unless changed by the user.
>         The shell updates cwd, dirstack, owd and  status  when  necessary,  and
>         sets logout on logout.
>
>         The shell synchronizes group, home, path, shlvl, term and user with the
>         environment variables of the same names: whenever the environment vari-
>         able  changes  the  shell  changes  the corresponding shell variable to
>         match (unless the shell variable is read-only) and  vice  versa.   Note
>         that  although  cwd  and PWD have identical meanings, they are not syn-
>         chronized in this manner, and that the  shell  automatically  intercon-
>         verts the different formats of path and PATH.
>
> [...]
>
>         home    Initialized to the home directory of the invoker.  The filename
>                 expansion of `~' refers to this variable.
>
> [...]
>
>         HOME    Equivalent to the home shell variable.
>
>
>
>
+1
Shell make no use of $Home.