linux equivalent to AIX proctree command to show all child and parent processes of a given PID

Question

Sometimes I'm looking for an equivalent for the AIX proctree command which displays all children and all ancestors of a specified PID and can be sometimes quite useful for troubleshooting purposes. As an example here's an excerpt of the man page:

To display the ancestors and children of process 12312,
including children of process 0, enter:

   proctree -a 12312

The output of this command might look like this:
1    /etc/init                                  
   4954    /usr/sbin/srcmstr                    
      7224    /usr/sbin/inetd                   
         5958    telnetd -a                     
            13212    -sh                        
               14724    ./proctree -a 13212

Another useful form that I use sometimes is proctree $$ which will also show my current terminal, and whether I logged in via ssh or via console.

For clarification, I'm not looking for a script that emulates this on linux but an actual equivalent that may already be existent.

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On linux, pstree shows all child processes of a specified PID, but the root will always be the specified PID (or init if no PID is specified and a complete tree will be shown).

Something like ps --forest -u "$username" does also not help as it only shows the processes of a given user, and it shows all of them - not only the ones of a given tree.

Solution

I think pstree -s 12312 gives what you want, if not in as nice a format.

Comments

[The Sidhekin]

Heh. Meanwhile, I totally missed that -a specifies (implies?) tree formatting. Thanks. :)

[doktor5000]

Yes, seems it does, that is also hidden in the man-page: [...] -a implicitly disables compaction for processes but not threads.