mjhjmtu

I want to create a log file for a cron script that has the current hour in the log file name. This is the command I tried to use:

0 * * * * echo hello >> ~/cron-logs/hourly/test`date "+%d"`.log

Unfortunately I get this message when that runs:

/bin/sh: -c: line 0: unexpected EOF while looking for matching ``'
/bin/sh: -c: line 1: syntax error: unexpected end of file

I have tried escaping the date part in various ways, but without much luck. Is it possible to make this happen in-line in a crontab file or do I need to create a shell script to do this?

Short answer:

Try this:

0 * * * * echo hello >> ~/cron-logs/hourly/test`date "+%d"`.log

Note the backslash escaping the % sign.

Long answer:

The error message suggests that the shell which executes your command doesn't see the second back tick character:

/bin/sh: -c: line 0: unexpected EOF while looking for matching ``'

This is also confirmed by the second error message your received when you tried one of the other answers:

/bin/sh: -c: line 0: unexpected EOF while looking for matching `)'

The crontab manpage confirms that the command is read only up to the first unescaped % sign:

The "sixth" field (the rest of the line) specifies the command to
be run. The entire command portion of the line, up to a newline or
% character, will be executed by /bin/sh or by the shell specified in
the SHELL variable of the cronfile. Percent-signs (%) in the
command, unless escaped with backslash (), will be changed into
newline charac- ters, and all data after the first % will be sent to
the command as standard input.

You can also put your commands into a shell file and then execute the shell file with cron.

jobs.sh

echo hello >> ~/cron-logs/hourly/test`date "+%d"`.log

cron

0 * * * * sh jobs.sh

If you would like to make the date formatting string as a variable (to avoid duplicating the whole string), DO NOT escape % and DO NOT put it in $()

For example, while declare the string, just write:

DATEVAR=date +%Y%m%d_%H%M%S

Then, write cron statement with $($VARIABLE_NAME) like this:

* * * * * /bin/echo $($DATEVAR) >> /tmp/crontab.log

Thanks to cyberx86, her/his answer at ServerFault might be more completed:

In cron, you can use this simple syntax:

*/15 01-09 * * * sh /script.sh >> /home/username/cron_$(date -d"-0 days" +%Y%m%d).log 2>&1