You want to login to Sybase ASE database using the iSQL utility.
Windows
Login with [sid]adm, open the command prompt and execute the following command,
sapsa user
isql -Usapsa -S[SID] -X (press Enter) Password: (enter your password here)
sa user
isql -Usa -S[SID] -X (press Enter) Password: (enter your password here)
UNIX / Linux
Login as [sid]adm or login as root and switch to [sid]adm. Execute the following command,
sapsa user
isql -Usapsa -S[SID] -X (press Enter) Password: (enter your password here)
sa user
isql -Usapsa -S[SID] -X (press Enter) Password: (enter your password here)