![]() ![]() Both of them have been introduced after the fundamental shell syntax was already stable, so they had to find a way to introduce new syntax which didn't already have a well-established meaning in the original Bourne shell. The shell command substitution $(command) and arithmetic evaluation $((expression)) syntaxes look vaguely similar, but are really unrelated. from datetime import datetime, timedeltaĭt = datetime.strptime(when,'%Y%m%d%H%M') If you have GNU date (that's a big if if you really want to target any Unix) you could simply have done date -u -d "60 minutes ago" +%F%H%Mīut if you are doing this from Python anyway, performing the date extraction and manipulation in Python too will be a lot more efficient as well as more portable. To subtract 60 from the value and echo that - but of course, date arithmetic isn't that simple subtracting 60 from 201908210012 will not produce 201908202312 like you would hope. Rather than perform arithmetic evaluation. Which of course will output the literal string 201908201834 - 60 If the plan is to capture the output to the variable now, the syntax for that is now=$(date -u +"%Y%m%d%H%M") This assigns an empty string to the variable now and then runs the date command as previously. When scheduling the job, the command warns the user which shell it will use during execution.Your current attempt has some simple shell script errors. The SHELL environment variable value determines which shell (bash, zsh, etc.) the at command uses to execute the job. Further specify the time using the + character.įor example, the following command schedules an echo command invocation five minutes after scheduling the job: echo "hello" | at now +5 minutes Using time expressions such as tomorrow or tuesday, schedules the jobs on those days at the current time. Specify a relative time expression by adding a plus sign ( +), the amount, and one of the following: The day after the current day.įor example, the following command schedules an echo command invocation at 5PM: echo "hello" | at 5PM The problem in my example is that in my timezone, daylight saving time starts between the two dates so the number of seconds between the two dates is short by 3600 (1 hour). kennyut at 14:09 1 kennyut The answer should actually be 92 days. ![]() Indicates the current day and time and immediate execution. Exactly the same commands, mine returns '92 days'. Specify a full year, month, day, hour, minute, and optionally seconds. Specify an abbreviated year, month, day, hour, minute, and optionally seconds. The available absolute time expressions are: Schedule a job using absolute time expressions or time expressions relative to the time of setting the job. Schedules a job for the time specified by the argument. The time format is Thu Feb 20 14:50:00 1997.Ĭats the specified job, showing its contents in standard command-line output. Shows the job execution time before reading the job. Deletes the scheduled jobs, identified by their job number. If the user is superuser, lists all users' pending jobs.Īn alias for atrm. Schedules jobs and executes them in a batch queue when the system load level average is below 1.5.Īn alias for atq. Reads the job from the specified rather than from standard input.Īn alias for batch. Requires a configured email address for the user that scheduled the job. Appointing a queue to atq causes it to show only jobs pending in that queue.Įmails the user after the job has completed, even if there was no output. The batch load average rules apply once it is time to execute the job. Submitting a job to a queue with an uppercase letter treats the job as submitted to batch. Queues with higher letters run with increased niceness. The a queue is the default for at and the b queue is the default for batch. You need to subtract 5 minutes from a known point in time: date -d '00:00:00 today' Thu Oct 8 00:00: date -d '00:00:00 today -5 minutes' Wed Oct 7 23:55. Note that during testing this option behaved exactly as r does, as shown below. X: Prints the time according to your locale, using the 24-hour clock. ![]() r: Prints the time according to your locale, using the 12-hour clock and an am or pm indicator. Uses the specified consisting of a single letter, ranging from a- z and A- Z. R: Prints the hour and minutes as HH:MM with no seconds, using the 24-hour clock. Prints the program version number to standard output. The options allow you to view or delete scheduled jobs and customize at command job scheduling. The syntax for the at command is: at runtime ![]()
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