Software & Apps Linux Learn the Linux Command - cal Display a calendar within your shell session Share Pin Email Print Linux Switching from Windows By Juergen Haas Writer Former Lifewire writer Juergen Haas is a software developer, data scientist, and a fan of the Linux operating system. our editorial process Juergen Haas Updated February 05, 2020 The Linux cal program displays a simple calendar. If arguments are not specified, the current month is displayed. Synopsis The command takes the following form: cal [-smjy13 ] [[ month ] year ] Options Specify switches to modify the command's output: -1: Display single month output. (This is the default.)-3: Display prev/current/next month output.-s: Display Sunday as the first day of the week. (This is the default.)-m: Display Monday as the first day of the week.-j: Display Julian dates (days one-based, numbered from Jan. 1).-y: Display a calendar for the current year. Usage Notes A single parameter specifies the year (1 - 9999) to be displayed; note the year must be fully specified: cal 89 will not display a calendar for 1989. Two parameters denote the month (1 - 12) and year. If no parameters are specified, the current month's calendar is displayed. A year starts on Jan 1. The Gregorian Reformation is assumed to have occurred on Sept. 3, 1752. By this time, most countries had recognized the reformation (although a few did not recognize it until the early 1900's.) Ten days following that date were eliminated by the reformation, so the calendar for that month is a bit unusual.