How can I change the format of a date from the command line?

Question

What\'s the quickest way to convert a date in one format, say

2008-06-01

to a date in another format, say

Answer 1

$ date -d '2005-06-30' +'%a %F'
Thu 2005-06-30

See man date for other format options.

This option is available on Linux, but not on Darwin. In Darwin, you can use the following syntax instead:

date -j -f "%Y-%m-%d" 2006-06-30 +"%a %F"

The -f argument specifies the input format and the + argument specifies the output format.

As pointed out by another poster below, you would be wise to use %u (numeric day of week) rather than %a to avoid localization issues.