Trying to get yesterdays date using the date command in a cronjob or cron variable

malbe · 05-24-2018, 12:04 PM

I am trying to add an argument with yesterdays date in a cronjob or make the date a variable in the crontab
I have tried several ways. I can get it to work with using todays date: `date +\%Y\%m\%d` but not yesterdays.

Yesterdays Date
* * * * * . $HOME/.bashrc; /usr/copy-dissem.py amsr2_nh `date --date="yesterday" +\%Y\%m\%d` >> /usr/amsr2_nh-dissem.log 2>&1

rtmistler · 05-24-2018, 12:12 PM

Does "yesterday" alone work in the cron job?
That format string and set of arguments in the normal shell seem to work fine.

malbe · 05-24-2018, 12:16 PM

Are you asking if just typing * * * * * . $HOME/.bashrc; /usr/copy-dissem.py amsr2_nh yesterday >> works? If so no it doesn't work.

rtmistler · 05-24-2018, 12:22 PM

No I was asking if you tried using the date command with --date="yesterday" only and did not include the format string. I was asking whether or not that worked.

* * * * * . $HOME/.bashrc; /usr/copy-dissem.py amsr2_nh `date --date="yesterday"` >> /usr/amsr2_nh-dissem.log 2>&1

malbe · 05-24-2018, 12:27 PM

Ok I tried it no luck. I think the problem area is the syntax of the quotation marks. The quotation marks show up red and give an error when I am creating the cronjob. I have tried other ways but they did not work.

`date --date=(yesterday) +\%Y\%m\%d`
`date --date='yesterday' +\%Y\%m\%d`

rtmistler · 05-24-2018, 12:54 PM

How about no quotation marks?

Also try removing the back slashes from the format string term.

But I'd try without the format string term to verify that the keyword yesterday works properly.

Along with "yesterday" you can instead do "-1 day" or '-1 day', but NOTE that those are forward single quotes.

michaelk · 05-24-2018, 01:29 PM

Since % is a cron special character they need to escaped if used in the command.
You might try replacing the back ticks with $() but I don't think it matters.

The command looks like it should work but try the others and see if what happens.

petelq · 05-24-2018, 02:01 PM

How about writing your command in a bash script and just using crontab to run the script.
I've found crontab a little choosy as to what instructions to follow.

keefaz · 05-24-2018, 04:16 PM

Quote:

Originally Posted by petelq

How about writing your command in a bash script and just using crontab to run the script.
I've found crontab a little choosy as to what instructions to follow.

Yes, when crontab lines tend to be long it's better to write commands in a script and let cron call this script. Also, it's easier to add variables if needed

michaelk · 05-24-2018, 05:49 PM

Here is the first attempt to duplicate the OPs cron problem. The basic cron job works with yesterday so something maybe different about their environment.

Code:

#!/bin/bash
echo $1 $2 >> /home/username/data.txt

Code:

* * * * * /home/username/my_program test1 $(date -d "yesterday" +\%Y\%m\%d\%M)
and

* * * * * /home/username/my_program test1 `date -d "yesterday" +\%Y\%m\%d\%M`

Code:

data.txt

test1 2018052325
test1 2018052326
test1 2018052327
test1 2018052328
test1 2018052329
test1 2018052330
test1 2018052331

test1 2018052342
test1 2018052343
test1 2018052344

yancek · 05-24-2018, 07:39 PM

I'm not really sure what you are trying to accomplish here but if you want output in YYYY MM DD format, output to a file, the command below worked for me in cron.

Code:

08 * * * * date --date "yesterday" > /home/user/data.txt

The date output to data.txt was:

Quote:

Wed May 23 17:12:01 MST 2018

Other options in cron such as below didn't output anything to the data.txt file although the command output the expected "2018\05\23" from a terminal and also worked in a script and output the date in format: 2018\05\23.

Quote:

date -d "yesterday" "+%Y\%m\%d" /home/user/data.txt