%
is a special character for crontab
. From man 5 crontab
:
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 a
"%" character, will be executed by /bin/sh or by the shell specified
in the SHELL variable of the cronfile. A "%" character in the
command, unless escaped with a backslash (\), will be changed into
newline characters, and all data after the first % will be sent to
the command as standard input.
So you need to escape the %
character:
curl -w "%{time_total}\n" -o /dev/null -s http://myurl.com >> ~/log
to
curl -w "\%{time_total}\n" -o /dev/null -s http://myurl.com >> ~/log
^