--- title: strftime summary: null url: >- https://www.fastly.com/documentation/reference/vcl/functions/date-and-time/strftime --- ``` STRING strftime(STRING format, TIME time) ``` **Available in:** all subroutines Formats a time to a string. This uses [standard POSIX strftime formats](https://www.unix.com/man-page/FreeBSD/3/strftime/). > **HINT:** Regular strings ("short strings") in VCL use `%xx` escapes (percent encoding) for special characters, which would conflict with the `%` used in the `strftime` format. For the `strftime` examples, we use VCL "long strings" `{"..."}`, which do not use the `%xx` escapes. Alternatively, you could use `%25` for each `%`. Valid format specifiers include: | Format | Substitution | | :----: | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `%a` | The abbreviated weekday name according to the current locale. | | `%A` | The full weekday name according to the current locale. | | `%b` | The abbreviated month name according to the current locale. | | `%B` | The full month name according to the current locale. | | `%c` | The preferred date and time representation for the current locale. | | `%C` | The century number (year/100) as a 2-digit integer. | | `%d` | The day of the month as a decimal number (range 01 to 31). | | `%D` | Equivalent to `%m`/`%d`/`%y`. | | `%e` | Like `%d`, the day of the month as a decimal number, but a leading zero is replaced by a space. | | `%F` | Equivalent to `%Y`-`%m`-`%d` (the [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) date format). | | `%G` | The [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) week-based year with century as a decimal number. The 4-digit year corresponding to the ISO week number (see `%V`). This has the same format and value as `%Y`, except that if the ISO week number belongs to the previous or next year, that year is used instead. | | `%g` | Like `%G`, but without century, that is; with a 2-digit year (00 to 99). | | `%h` | Equivalent to `%b`. | | `%H` | The hour as a decimal number using a 24-hour clock (range 00 to 23). | | `%I` | The hour as a decimal number using a 12-hour clock (range 01 to 12). | | `%j` | The day of the year as a decimal number (range 001 to 366). | | `%m` | The month as a decimal number (range 01 to 12). | | `%M` | The minute as a decimal number (range 00 to 59). | | `%n` | A newline character. | | `%p` | Either `AM` or `PM` according to the given time value, or the corresponding strings for the current locale. Noon is treated as `PM` and midnight as `AM`. | | `%r` | The time in a.m. or p.m. notation. In the POSIX locale this is equivalent to `%I`:`%M`:`%S` `%p`. | | `%R` | The time in 24-hour notation (`%H`:`%M`). For a version including the seconds, see `%T`. | | `%s` | The number of seconds since the epoch; that is, since 1970-01-01 00:00:00 UTC. | | `%S` | The second as a decimal number (range 00 to 60). (A range up to 60 allows for occasional leap seconds.) | | `%t` | A tab character. | | `%T` | The time in 24-hour notation (`%H`:`%M`:`%S`). | | `%u` | The day of the week as a decimal, range 1 to 7, Monday being 1. See also `%w`. | | `%U` | The week number of the current year as a decimal number, range 00 to 53, starting with the first Sunday as the first day of week 01. See also `%V` and `%W`. | | `%V` | The [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) week number of the current year as a decimal number, range 01 to 53, where week 1 is the first week that has at least four days in the new year. See also `%U` and `%W`. | | `%w` | The day of the week as a decimal, range 0 to 6, Sunday being 0. See also `%u`. | | `%W` | The week number of the current year as a decimal number, range 00 to 53, starting with the first Monday as the first day of week 01. | | `%x` | The preferred date representation for the current locale, without the time. | | `%X` | The preferred time representation for the current locale, without the date. | | `%y` | The year as a decimal number without a century (range 00 to 99). | | `%Y` | The year as a decimal number, including the century. | | `%z` | The time-zone as an hour offset from GMT. Required to emit [RFC 822](https://tools.ietf.org/html/rfc822)-conformant dates (using `%a`, `%d` `%b` `%Y` `%H`:`%M`:`%S` `%z`). | | `%Z` | The timezone or name or abbreviation. | | `%%` | A literal `%` character. | Format specifiers which produce numbers may include one of the following flags after the `%`: | Flag | Modification | | :--: | :---------------------- | | `0` | Use zeros for padding. | | `_` | Use spaces for padding. | | `-` | Do not use any padding. | For example, `%-H` would produce `3` while `%H` would produce `03`. The POSIX standard `E` and `O` modifier characters have no effect. For example, `%Ec` is equivalent to `%c`. This function is not prefixed with the `std.` namespace. ## Examples ```vcl # Concise format set resp.http.now = strftime({"%Y-%m-%d %H:%M"}, now); # resp.http.now is now e.g. 2006-01-02 22:04 # RFC 5322 format set resp.http.start = strftime({"%a, %d %b %Y %T %z"}, time.start); # resp.http.start is now e.g. Mon, 02 Jan 2006 22:04:05 +0000 # ISO 8601 format set resp.http.end = strftime({"%Y-%m-%dT%H:%M:%SZ"}, time.end); # resp.http.end is now e.g. 2006-01-02T22:04:05Z ```