1clock(n) Tcl Built-In Commands clock(n)
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8 clock - Obtain and manipulate time
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11 clock option ?arg arg ...?
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16 This command performs one of several operations that may obtain or
17 manipulate strings or values that represent some notion of time. The
18 option argument determines what action is carried out by the command.
19 The legal options (which may be abbreviated) are: │
20 clock clicks ?-milliseconds? │
22 Return a high-resolution time value as a system-dependent inte‐ │
23 ger value. The unit of the value is system-dependent but should │
24 be the highest resolution clock available on the system such as │
25 a CPU cycle counter. If -milliseconds is specified, then the │
26 value is guaranteed to be of millisecond granularity. This │
27 value should only be used for the relative measurement of │
28 elapsed time.
29 clock format clockValue ?-format string? ?-gmt boolean?
31 Converts an integer time value, typically returned by clock sec‐
32 onds, clock scan, or the atime or mtime options of the file com‐
33 mand, to human-readable form. If the -format argument is
34 present the next argument is a string that describes how the
35 date and time are to be formatted. Field descriptors consist of
36 a % followed by a field descriptor character. All other charac‐
37 ters are copied into the result. Valid field descriptors are:
38 %% Insert a %.
40 %a Abbreviated weekday name (Mon, Tue, etc.).
42 %A Full weekday name (Monday, Tuesday, etc.).
44 %b Abbreviated month name (Jan, Feb, etc.).
46 %B Full month name. │
48 %c │
50 Locale specific date and time. The format for date and │
51 time in the default "C" locale on Unix/Mac is "%a %b %d │
52 %H:%M:%S %Y". On Windows, this value is the locale spe‐ │
53 cific long date and time, as specified in the Regional │
54 Options control panel settings. │
55 %C │
57 First two digits of the four-digit year (19 or 20).
58 %d Day of month (01 - 31). │
60 %D │
62 Date as %m/%d/%y. │
63 %e │
65 Day of month (1 - 31), no leading zeros. │
66 %g │
68 The ISO8601 year number corresponding to the ISO8601 week │
69 (%V), expressed as a two-digit year-of-the-century, with │
70 leading zero if necessary. │
71 %G │
73 The ISO8601 year number corresponding to the ISO8601 week │
74 (%V), expressed as a four-digit number. │
75 %h │
77 Abbreviated month name.
78 %H Hour in 24-hour format (00 - 23). │
80 %I │
82 Hour in 12-hour format (01 - 12).
83 %j Day of year (001 - 366). │
85 %k │
87 Hour in 24-hour format, without leading zeros (0 - 23). │
88 %l │
90 Hour in 12-hour format, without leading zeros (1 - 12).
91 %m Month number (01 - 12).
93 %M Minute (00 - 59). │
95 %n │
97 Insert a newline.
98 %p AM/PM indicator. │
100 %r │
102 Time in a locale-specific "meridian" format. The "merid‐ │
103 ian" format in the default "C" locale is "%I:%M:%S %p". │
104 %R │
106 Time as %H:%M. │
107 %s │
109 Count of seconds since the epoch, expressed as a decimal │
110 integer.
111 %S Seconds (00 - 59). │
113 %t │
115 Insert a tab. │
116 %T │
118 Time as %H:%M:%S. │
119 %u │
121 Weekday number (Monday = 1, Sunday = 7).
122 %U Week of year (00 - 52), Sunday is the first day of the
124 week. │
125 %V │
127 Week of year according to ISO-8601 rules. Week 1 of a │
128 given year is the week containing 4 January. │
129 %w │
131 Weekday number (Sunday = 0, Saturday = 6).
132 %W Week of year (00 - 52), Monday is the first day of the
134 week. │
135 %x │
137 Locale specific date format. The format for a date in │
138 the default "C" locale for Unix/Mac is "%m/%d/%y". On │
139 Windows, this value is the locale specific short date │
140 format, as specified in the Regional Options control │
141 panel settings. │
142 %X │
144 Locale specific 24-hour time format. The format for a │
145 24-hour time in the default "C" locale for Unix/Mac is │
146 "%H:%M:%S". On Windows, this value is the locale spe‐ │
147 cific time format, as specified in the Regional Options │
148 control panel settings.
149 %y Year without century (00 - 99).
151 %Y Year with century (e.g. 1990)
153 %Z Time zone name.
155 If the -format argument is not specified, the format string "%a │
157 %b %d %H:%M:%S %Z %Y" is used. If the -gmt argument is present
158 the next argument must be a boolean which if true specifies that
159 the time will be formatted as Greenwich Mean Time. If false then
160 the local timezone will be used as defined by the operating
161 environment.
162 clock scan dateString ?-base clockVal? ?-gmt boolean?
164 Convert dateString to an integer clock value (see clock sec‐
165 onds). This command can parse and convert virtually any stan‐
166 dard date and/or time string, which can include standard time
167 zone mnemonics. If only a time is specified, the current date
168 is assumed. If the string does not contain a time zone
169 mnemonic, the local time zone is assumed, unless the -gmt argu‐
170 ment is true, in which case the clock value is calculated assum‐
171 ing that the specified time is relative to Greenwich Mean Time.
172 -gmt, if specified, affects only the computed time value; it
173 does not impact the interpretation of -base.
174 If the -base flag is specified, the next argument should contain
176 an integer clock value. Only the date in this value is used,
177 not the time. This is useful for determining the time on a spe‐
178 cific day or doing other date-relative conversions.
179 The dateString consists of zero or more specifications of the
181 following form:
182 time A time of day, which is of the form: hh?:mm?:ss??
184 ?meridian? ?zone? or hhmm ?meridian? ?zone?. If no
185 meridian is specified, hh is interpreted on a 24-hour
186 clock.
187 date A specific month and day with optional year. The accept‐
189 able formats are mm/dd?/yy?, monthname dd ?, yy?, dd mon‐
190 thname ?yy?, day, dd monthname yy, ?CC?yymmdd, ?CC?yy-mm-
191 dd, dd-monthname-?CC?yy. The default year is the current
192 year. If the year is less than 100, we treat the years │
193 00-68 as 2000-2068 and the years 69-99 as 1969-1999. Not │
194 all platforms can represent the years 38-70, so an error │
195 may result if these years are used.
196 ISO 8601 point-in-time
198 An ISO 8601 point-in-time specification, such as CCyymmd‐
199 dThhmmss, where T is the literal T, CCyymmdd hhmmss, or
200 CCyymmddThh:mm:ss. Note that only these three formats
201 are accepted. The command does not accept the full range
202 of point-in-time specifications specified in ISO8601.
203 Other formats can be recognized by using commands such as
204 regexp to extract their fields and reorganize them into a
205 form accepted by the clock scan command.
206 relative time
208 A specification relative to the current time. The format
209 is number unit acceptable units are year, fortnight,
210 month, week, day, hour, minute (or min), and second (or
211 sec). The unit can be specified as a singular or plural,
212 as in 3 weeks. These modifiers may also be specified:
213 tomorrow, yesterday, today, now, last, this, next, ago.
214 The actual date is calculated according to the following steps.
216 First, any absolute date and/or time is processed and converted.
217 Using that time as the base, day-of-week specifications are
218 added. Next, relative specifications are used. If a date or
219 day is specified, and no absolute or relative time is given,
220 midnight is used. Finally, a correction is applied so that the
221 correct hour of the day is produced after allowing for daylight
222 savings time differences and the correct date is given when
223 going from the end of a long month to a short month.
224 Daylight savings time correction is applied only when the rela‐
226 tive time is specified in units of days or more, ie, days,
227 weeks, fortnights, months or years. This means that when cross‐
228 ing the daylight savings time boundary, different results will
229 be given for clock scan "1 day" and clock scan "24 hours":
230 % clock scan "1 day" -base [clock scan 1999-10-31]
231 941443200
232 % clock scan "24 hours" -base [clock scan 1999-10-31]
233 941439600
234 clock seconds
236 Return the current date and time as a system-dependent integer
237 value. The unit of the value is seconds, allowing it to be used
238 for relative time calculations. The value is usually defined as
239 total elapsed time from an ``epoch''. You shouldn't assume the
240 value of the epoch.
241
244 date(1), time(n)
245
248 clock, date, time
249Tcl 8.4 clock(n)