Curl – Exclamation mark in User Auth/Password

 curl -u UserName\\WithSlash:PasswordWithExclamation\!  http://....

works fine.

it sends

 GET / HTTP/1.1
 Authorization: Basic VXNlck5hbWVcV2l0aFNsYXNoOlBhc3N3b3JkV2l0aEV4Y2xhbWF0aW9uIQ==
 User-Agent: curl/7.21.0
 Host: teststuff1.com:80
 Accept: */*

which is “UserName\WithSlash:PasswordWithExclamation!” in the auth string.