How to Use Date Command in Bash: Syntax and Examples

Use the date command in bash to display or format the current date and time. You can customize the output by adding format options with +FORMAT, where format codes like %Y or %m represent year and month.

Syntax

The basic syntax of the date command is:

• date: Shows the current date and time.
• date +FORMAT: Displays the date/time formatted according to FORMAT.
• date -d "STRING": Shows the date/time for a specified date/time string.

Format codes start with % and represent parts of the date/time, like year, month, day, hour, minute, and second.

bash

date [+FORMAT]
date -d "STRING" [+FORMAT]

Example

This example shows how to display the current date in Year-Month-Day format and how to get the date for tomorrow.

bash

date +"%Y-%m-%d"
date -d "tomorrow" +"%Y-%m-%d"

Output

2024-06-15
2024-06-16

Common Pitfalls

Common mistakes include forgetting the + before the format string, which causes the command to print the literal string instead of formatting the date. Another is using unsupported format codes or incorrect date strings with -d.

Always enclose format strings in quotes to avoid shell interpretation issues.

bash

date "%Y-%m-%d"  # Wrong: missing +
date +"%Y-%m-%d"  # Correct

date -d "next week" +"%Y-%m-%d"  # Correct usage of -d

Quick Reference

Format Code	Meaning	Example Output
%Y	Year (4 digits)	2024
%m	Month (01-12)	06
%d	Day of month (01-31)	15
%H	Hour (00-23)	14
%M	Minute (00-59)	30
%S	Second (00-59)	05
%a	Abbreviated weekday	Sat
%A	Full weekday name	Saturday

Key Takeaways

Use date +FORMAT to customize date output with format codes.

Always prefix format strings with + and enclose them in quotes.

Use date -d "STRING" to get dates for relative or specific times.

Common format codes include %Y for year, %m for month, and %d for day.

Test your date commands to avoid syntax errors and unexpected outputs.