Cron / Cron Service
Instructions
Please also have a look at pycron. It's a more recent development with more features.
Cron scans the file CRONTAB every minute and checks every line if the specified time/date information matches the current time/date. If they are equal, the command line specified will be executed. A log file (cron.log) with the executed commands is written to the current directory.
Download
There are two versions of Cron:
| Version: |
Download link: |
| Cron for Windows 9x/NT |
|
| Cron NT service
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Setup for first version (Windows 9x/NT)
- copy the files cron.exe and crontab to a folder of your choice
- edit the file crontab (see the examples as a reference)
- create a link to cron.exe and move it to the startup folder
Setup for NT service
- create a crontab file in your SYSTEM32 folder
- execute the included ntsetup.exe
- call "crons.exe /?" in a command line to see the available options of crons
The Crontab file
Each line of CRONTAB has the following structure:
<Minute> <Hour> <Day> <Month> <Day of Week> <Command line>
| Position: |
Values: |
| Minute |
0-59 |
| Hour |
0-23 |
| Day |
1-31 |
| Month |
1-12 |
| Day of week |
0-6 (0=Sunday, 1=Monday, ..., 6=Saturday) |
Instead of minute, hour, day, month or day of week it's also possible to specify a *. A * represents all possible values for that position (e.g. a * on 2nd position is the same as specifying all the possible values for hour)
It's also possible to specify several values separated by commas: e.g. if you want a command to be executed every 10th minute so you can specify 0,10,20,30,40,50 for minute. A range of values can be specified with a -: e.g. value 0-12 for hour -> every hour a.m.
Comments
Every line not starting with a number is treated as a comment.
Examples
execute a command every minute
# This is a comment.
* * * * * c:\tools\CheckForNewFiles.exe
execute the program backup.bat every hour
# This is a comment.
0 * * * * c:\tests\backup.bat
do a backup every day at 0.30 p.m.
# This is a comment.
30 12 * * * c:\tests\backup.bat
start a backup every tuesday at midnight
# This is a comment.
0 0 * * 3 c:\tests\backup.bat
scan drive c for viruses on the 1st of every month at 2.45 p.m.
# scan for known viruses
45 14 1 * * c:\path_to_scanner\scan c:
copy some files every half hour
# This is a comment.
0,30 * * * * xcopy c:\docs\*.* y:\users /s
copy a file every hour (a.m.) only on weekdays
# System commands need the command interpreter specified:
0 0-12 * * 1-5 c:\...\cmd.exe /c "copy c:\... e:\"