cal

Updated

September 4, 2026

Overview

cal displays a calendar in the terminal — current month by default, or a specific month/year. Handy for quick date context, scripting reminders, and verifying week boundaries. Some systems ship ncal with alternate layouts.

Syntax

cal [options] [[[day] month] year]
cal [options] [[month] year]
cal [options] -y [year]

Exact syntax variants exist between util-linux cal and BSD-style cal/ncal.

Common Options (util-linux / common)

Option	Description
`-1` / `-3`	One month / three months
`-y`	Whole year
`-m`	Monday as first day of week
`-s`	Sunday first (when supported)
`-w`	Week numbers
`-j`	Julian day numbers
`-A n` / `-B n`	Months after / before
`-h`	Highlight off (or help, depending on version)
`--color`	Colorize today (newer)

Check cal --help on your host.

Examples with Explanations

Current month

cal
cal -3
cal -m
cal -w

Specific month / year

cal 12 2026
cal 2026
cal -y 2026

Week numbers for planning

cal -w
cal -mw 9 2026

Surrounding months

cal -A 1 -B 1
cal -3

Historical curiosity

cal 9 1752                 # UK calendar reform month (implementation-dependent)

Scripts: parse carefully

# better for machine dates:
date +%F
date +%V                   # ISO week
# use cal for human display only

ncal alternative

ncal
ncal -b
ncal -w

Notes / Pitfalls

Highlighting “today” depends on terminal and build options.
Week-start Monday/Sunday differs by locale and flags — be explicit with -m when it matters.
Do not parse cal output for business logic; use date and proper libraries.
Year range limits differ; very ancient/future years may error.
BusyBox cal is minimal.

2026-relevant notes

ISO week numbers (date +%V, cal -w) still matter for release trains and on-call rotations.
Prefer date for automation; keep cal as a human aid over SSH.
Terminal Unicode width issues can misalign rare locales.

Additional Resources

man cal, man ncal