Using `date '+%Y%m%d'` in crontab?

stefanlasiewski · 01-06-2006, 12:49 PM

Hey everyone,

I'm trying to figure out how to use cron to generate a file containing today's date, such as 'ls.log.20060105'.

I know Cron uses /bin/sh .

If I switch to /bin/sh , the command "ls foo bar > ls.log.`date +%Y%m%d` 2>&1" creates the file correctly. However, the file is NOT created when I put this same command in my crontab.

I've tried the following methods, and none of them create the file 'ls.log.20060105':

Code:

0 10 * * * ls foo bar > ls.log.`date +%Y%m%d` 2>&1

# Use a variable
0 10 * * * DATE=`date +%Y%m%d` ; ls foo bar > ls.log.$DATE 2>&1

# Use single quotes
0 10 * * * DATE=`date '+%Y%m%d'` ; ls foo bar > ls.log.$DATE 2>&1

# Escape the % characters with a \
0 10 * * * DATE=`date +\%Y\%m\%d` ; ls foo bar > ls.log.$DATE 2>&1

# Use single quotes AND escape the % characters with a \
0 10 * * * DATE=`date '+\%Y\%m\%d'` ; ls foo bar > ls.log.$DATE 2>&1

I appreciate any help,

Thank you,
-= Stefan

MensaWater · 01-06-2006, 01:13 PM

Try putting in the full path of the date command instead of just date. (e.g. /bin/date).

Matir · 01-06-2006, 01:56 PM

Also, I don't think variable expansion works well (if at all) in cronjobs. Rather than using $DATE, try (as you did in your test) just putting the expression there with the backticks.

stefanlasiewski · 01-06-2006, 02:03 PM

Excellent. Thanks for the help. Cron drives me crazy.

It works when I use the full path to 'date', no variable expansion (although that does work on some OSes), and escaping with backslashes works fine.

Code:

0 11 * * * ls foo bar > ls.log.`/usr/bin/date +\%Y\%m\%d` 2>&1

Thanks again!

Matir · 01-06-2006, 02:06 PM

Cron can be a beast sometimes. Most often when I need to do something of any complexity, I write a (small) script to do it and have cron just call that script for cleanliness.

thamarin · 06-29-2015, 01:32 AM

i use scrip sample

DB-`date +%Y-%m-%d`

DB it uppercase

The result has been db-2015-06-28

i don't understand

help me!

MensaWater · 07-01-2015, 02:25 PM

You should probably open a new thread for your question.

Giving us just the DB-.... doesn't help. We'd need to see what the script is doing at least in the section where you have that and probably the entire script. There are tools in Linux to convert upper case to lower case but nothing does it automatically without you telling it to do so. Without seeing the whole script we can't tell what is doing this in your script.