cal - macOS

Overview

The cal command in macOS displays a calendar in the terminal, showing a simple visual representation of months and years according to the Gregorian calendar. Its primary purpose is to provide users with quick calendar reference directly from the command line. This tool is particularly useful for scheduling, planning, and date checking within terminal workflows.

Syntax

The basic syntax of the cal command is as follows:

cal [options] [[month] year]

Where month and year are optional arguments specifying the month and year to display. If not provided, cal displays the calendar for the current month.

Options/Flags

-m: Start the calendar week with Monday. By default, weeks start on Sunday.
-y: Display a calendar for the entire year. If a year is not specified, it defaults to the current year.
-3: Display the previous month, the current month, and the next month all at once.

Typical Use Cases:

Use the -m option to align with international week standards where the week begins on Monday.
The -y option is ideal for people needing an overview of the entire year for planning or reference.
The -3 option can help in planning or transitioning across months by providing a broader view.

Examples

Display the current month’s calendar:
```
cal
```
Display the calendar for an entire year:
```
cal -y 2023
```
Display the calendar for a specific month and year:
```
cal 11 2023
```
Display calendars for the previous, current, and next month:
```
cal -3
```
Display the current year’s calendar with weeks starting on Monday:
```
cal -m -y
```

Common Issues

Wrong Month/Year Specified: Users sometimes experience confusion when they accidentally input incorrect month or year values. Double-check values before executing the command.
Formatting Issues on Small Terminals: The calendar may appear disorganized on small terminal windows. Maximize the terminal or use the command on a larger display.

Integration

cal can be integrated with other commands for more complex scripts:

Print a headed calendar:
```
echo "Month Overview:" && cal
```
Save the current month’s calendar to a text file:
```
cal > current_month.txt
```
Combine with grep to find specific days:
```
cal 2023 | grep -w "Fri"
```

date: Displays or sets the system date and time, often used together with cal for scripts involving date calculations.
ncal: Offers a different layout/view for the calendar compared to the traditional cal.

For more details, consult the manual pages using the man command, such as man cal or visit macOS Terminal User Guide online.