Syntax error only when command is run from cron

Question

This command:

/usr/bin/mysqldump --add-drop-table -u myuser -pmypass mydb > "/home/myuser/dbBackups/"`date +%Y%m%d`".sql"

works fine from the command line but whenb cron runs it I get

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

The command is all on one line in the crontab as well so I'm confused by the line 0 and line 1 references...

Can anyone advise me as to what I am doing wrong there?

Answer 1

It's the obvious dumb question, but do you have the matching backquote in your crontab (crontab -l)?

The line one, line zero stuff isn't referring to the lines in the crontab, only to the 'lines' in the one-line script.

Updated:

Ah, I think I've got it. This is from crontab(5):

Percent-signs (%) in the command, unless escaped with backslash (\),
will be changed into newline characters, and all data after the
first % will be sent to the command as standard input.

So the percent characters in your date spec are being interpreted as newlines, which means the backquote isn't terminated before the newline, which would produce your error message.

So escape the percent characters. I'd forgotten that about crontab....