date time.bash

# Format Current Date
date +%Y-%m-%d\ %H:%M:%S

# Reformatting string date
# most distros
date -d'27 JUN 2011' +%Y%m%d
# => 20110627
# os x / BSD
date -jf "%m %d %Y" "07 08 1990" +%Y-%m-%d
# => 1990-07-08


# [HowTo Format Date For Display or Use In a Shell Script](http://www.cyberciti.biz/faq/linux-unix-formatting-dates-for-display/)

# Examples

date +%Y-%m-%d-%H-%M-%S
# 2015-11-12-11-36-46

date +%H
# 11

# %FORMAT String    Description
# %%    a literal %
# %a    locale's abbreviated weekday name (e.g., Sun)
# %A    locale's full weekday name (e.g., Sunday)
# %b    locale's abbreviated month name (e.g., Jan)
# %B    locale's full month name (e.g., January)
# %c    locale's date and time (e.g., Thu Mar 3 23:05:25 2005)
# %C    century; like %Y, except omit last two digits (e.g., 21)
# %d    day of month (e.g, 01)
# %D    date; same as %m/%d/%y
# %e    day of month, space padded; same as %_d
# %F    full date; same as %Y-%m-%d
# %g    last two digits of year of ISO week number (see %G)
# %G    year of ISO week number (see %V); normally useful only with %V
# %h    same as %b
# %H    hour (00..23)
# %I    hour (01..12)
# %j    day of year (001..366)
# %k    hour ( 0..23)
# %l    hour ( 1..12)
# %m    month (01..12)
# %M    minute (00..59)
# %n    a newline
# %N    nanoseconds (000000000..999999999)
# %p    locale's equivalent of either AM or PM; blank if not known
# %P    like %p, but lower case
# %r    locale's 12-hour clock time (e.g., 11:11:04 PM)
# %R    24-hour hour and minute; same as %H:%M
# %s    seconds since 1970-01-01 00:00:00 UTC
# %S    second (00..60)
# %t    a tab
# %T    time; same as %H:%M:%S
# %u    day of week (1..7); 1 is Monday
# %U    week number of year, with Sunday as first day of week (00..53)
# %V    ISO week number, with Monday as first day of week (01..53)
# %w    day of week (0..6); 0 is Sunday
# %W    week number of year, with Monday as first day of week (00..53)
# %x    locale's date representation (e.g., 12/31/99)
# %X    locale's time representation (e.g., 23:13:48)
# %y    last two digits of year (00..99)
# %Y    year
# %z    +hhmm numeric timezone (e.g., -0400)
# %:z   +hh:mm numeric timezone (e.g., -04:00)
# %::z  +hh:mm:ss numeric time zone (e.g., -04:00:00)
# %:::z numeric time zone with : to necessary precision (e.g., -04, +05:30)
# %Z    alphabetic time zone abbreviation (e.g., EDT)