# Simply rename (if structure is compatible) mv file.vcs file.ics sed 's/VERSION:1.0/VERSION:2.0/g' file.vcs > file.ics Note: VCS (vCalendar 1.0) is older than ICS (iCalendar 2.0). Some fields may not convert perfectly; test the ICS file after conversion. Would you like a one-line command or script to batch convert many .vcs files to .ics ?