Try --data-urlencode with -G.

curl "http://127.0.0.1:13013/cgi-bin/sendsms?username=kannel&password=kannelpassword&to=03333333333" -G --data-urlencode text@/temp/message.txt

Try --data-urlencode with -G.

curl "http://127.0.0.1:13013/cgi-bin/sendsms?username=kannel&password=kannelpassword&to=03333333333" -G --data-urlencode text@/temp/message.txt

You can feed the data from stdin:

ls -l | curl "http://127.0.0.1:13013/..." -G --data-urlencode text@-

Or specify it directly on the command line:

curl "http://127.0.0.1:13013/..." -G --data-urlencode text='!@#$%^&*()'