Curl installation and basic usage

Installation of the curl is not so complicated. For Debian it is as follows:

apt-get install curl

You may also install php library:

apt-get install php5-curl

There are lot of options you may use in order to calling curl command from terminal. Two of them are useful when you’re trying to run heavy script : --connect-timeout and --max-time.  Second one is useful for preventing your batch jobs from hanging for hours due to slow connection. Here are quoting from manpage:

--connect-timeout 
    Maximum  time  in  seconds  that you allow the connection to the
    server to take.  This only limits  the  connection  phase,  once
    curl has connected this option is of no more use.  Since 7.32.0,
    this option accepts decimal values, but the actual timeout  will
    decrease in accuracy as the specified timeout increases in deci‐
    mal precision. See also the -m, --max-time option.

    If this option is used several times, the last one will be used.

-m, --max-time [seconds]
    Maximum  time  in  seconds that you allow the whole operation to
    take.  This is useful for preventing your batch jobs from  hang‐
    ing  for  hours due to slow networks or links going down.  Since
    7.32.0, this option accepts decimal values, but the actual time‐
    out will decrease in accuracy as the specified timeout increases
    in decimal precision.  See also the --connect-timeout option.

    If this option is used several times, the last one will be used.

Another important thing is a presence of special chars in url: ?, & etc. In this case you have to quote the url. For example:

curl 'https://www.somesite.com/somepath/somescript?get1=foo&get2=bar'