bash - 百分号 % 在 crontab 中不起作用

Question

我有一个关于 curl 的 cron 问题:

curl -w "%{time_total}\n" -o /dev/null -s http://myurl.com >> ~/log

效果很好，在日志文件中添加一行 total_time。

但是与 cron 相同的一行没有做任何事情。

这不是路径问题，因为 curl http://myurl.com >> ~/log 有效。

Answer 1

% 是crontab 的特殊字符。来自 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.

所以你需要转义%字符:

curl -w "%{time_total}\n" -o /dev/null -s http://myurl.com >> ~/log

到

curl -w "\%{time_total}\n" -o /dev/null -s http://myurl.com >> ~/log
         ^