A sample shell script
#!/bin/bash NOW=$(date +"%m-%d-%Y") FILE="backup.$NOW.tar.gz" echo "Backing up data to /nas42/backup.$NOW.tar.gz file, please wait..." # rest of script # tar xcvf /nas42/backup.$NOW.tar.gz /home/ /etc/ /var |
A complete list of FORMAT control characters supported by the GNU/date command
FORMAT controls the output. It can be the combination of any one of the following:
| %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) |
A complete list of FORMAT control characters supported by the BSD/date command
The following works on Apple OS X, FreeBSD and BSD version of the date command:
| %A | is replaced by national representation of the full weekday name. |
| %a | is replaced by national representation of the abbreviated weekday name. |
| %B | is replaced by national representation of the full month name. |
| %b | is replaced by national representation of the abbreviated month name. |
| %C | is replaced by (year / 100) as decimal number; single digits are preceded by a zero. |
| %c | is replaced by national representation of time and date. |
| %D | is equivalent to “%m/%d/%y”. |
| %d | is replaced by the day of the month as a decimal number (01-31). |
| %E* %O* | POSIX locale extensions. The sequences %Ec %EC %Ex %EX %Ey %EY %Od %Oe %OH %OI %Om %OM %OS %Ou %OU %OV %Ow %OW %Oy are supposed to provide alternate representations. Additionally %OB implemented to represent alternative months names (used standalone, without day mentioned). |
| %e | is replaced by the day of the month as a decimal number (1-31); single digits are preceded by a blank. |
| %G | is replaced by a year as a decimal number with century. This year is the one that contains the greater part of the week (Monday as the first day of the week). |
| %g | is replaced by the same year as in “%G”, but as a decimal number without century (00-99). |
| %H | is replaced by the hour (24-hour clock) as a decimal number (00-23). |
| %h | the same as %b. |
| %I | is replaced by the hour (12-hour clock) as a decimal number (01-12). |
| %j | is replaced by the day of the year as a decimal number (001-366). |
| %k | is replaced by the hour (24-hour clock) as a decimal number (0-23); single digits are preceded by a blank. |
| %l | is replaced by the hour (12-hour clock) as a decimal number (1-12); single digits are preceded by a blank. |
| %M | is replaced by the minute as a decimal number (00-59). |
| %m | is replaced by the month as a decimal number (01-12). |
| %n | is replaced by a newline. |
| %O* | the same as %E*. |
| %p | is replaced by national representation of either “ante meridiem” (a.m.) or “post meridiem” (p.m.) as appropriate. |
| %R | is equivalent to “%H:%M”. |
| %r | is equivalent to “%I:%M:%S %p”. |
| %S | is replaced by the second as a decimal number (00-60). |
| %s | is replaced by the number of seconds since the Epoch, UTC (see mktime(3)). |
| %T | is equivalent to “%H:%M:%S”. |
| %t | is replaced by a tab. |
| %U | is replaced by the week number of the year (Sunday as the first day of the week) as a decimal number (00-53). |
| %u | is replaced by the weekday (Monday as the first day of the week) as a decimal number (1-7). |
| %V | is replaced by the week number of the year (Monday as the first day of the week) as a decimal number (01-53). If the week containing January 1 has four or more days in the new year, then it is week 1; otherwise it is the last week of the previous year, and the next week is week 1. |
| %v | is equivalent to “%e-%b-%Y”. |
| %W | is replaced by the week number of the year (Monday as the first day of the week) as a decimal number (00-53). |
| %w | is replaced by the weekday (Sunday as the first day of the week) as a decimal number (0-6). |
| %X | is replaced by national representation of the time. |
| %x | is replaced by national representation of the date. |
| %Y | is replaced by the year with century as a decimal number. |
| %y | is replaced by the year without century as a decimal number (00-99). |
| %Z | is replaced by the time zone name. |
| %z | is replaced by the time zone offset from UTC; a leading plus sign stands for east of UTC, a minus sign for west of UTC, hours and minutes follow with two digits each and no delimiter between them (common form for RFC 822 date headers). |
| %+ | is replaced by national representation of the date and time (the format is similar to that produced by date(1)). |
| %-* | GNU libc extension. Do not do any padding when performing numerical outputs. |
| %_* | GNU libc extension. Explicitly specify space for padding. |
| %0* | GNU libc extension. Explicitly specify zero for padding. |
| %% | is replaced by %. |