Unix/Linux date FAQ: How do I create a formatted date in Linux? (Or, “How do I create a formatted date I can use in a Linux shell script?”)
I just ran into a case where I needed to create a formatted date in a Linux shell script, where the desired date format looks like this:
To create this formatted date string, I use the Linux
date command, adding the
+ symbol to specify that I want to use the date formatting option, like this:
date command shown in this line of code creates the date string in the format I want, and then I save the formatted date output to a Linux shell script variable named
This just shows one possible way to format a date in a Linux shell script. Of course you can use '-', '.', and many other characters as date field separators, or use no characters at all.
Note that after you have a formatted date for your shell script, you can create a filename variable like this:
In that example I’m creating a filename that’s unique every day, which I can later refer to as
$filename in my script.
More Linux date formatting information
For more information on other Linux date formatting options (there are many more date formatting options), take a look at the man page for the
date command on your Linux system, like this:
When I run that command on a CentOS Linux system, it shows these date-formatting operators:
%% 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)
As an example, here’s a time formatting example from 11:32am this morning:
$ t=`date +"%H.%M.%S"` $ echo $t 11.32.46
Because Unix and Linux systems are very consistent in this area, you should be able to write a date formatting command on one Unix or Linux system, and use that same command on another Unix system.