You can use both voicemail and call forwarding with Skype for Linux.
                      - To configure voicemail on Skype for Linux, click  and select Options > Voicemail. Here 
                        you can record a custom message and set when calls go 
                        to voicemail. and select Options > Voicemail. Here 
                        you can record a custom message and set when calls go 
                        to voicemail.
- To configure call forwarding on Skype for Linux, click  and select Options > Call Forwarding. Here 
                        you can set a number for calls to be forwarded to and 
                        how long a call should ring before it is forwarded. and select Options > Call Forwarding. Here 
                        you can set a number for calls to be forwarded to and 
                        how long a call should ring before it is forwarded.
Learn more about voicemail and 
                      call forwarding.