In interactive mode:

mssql-cmd> connect username:password@host:port/dbname;

example:

mssql-cmd> connect pan:withdata@192.168.0.102:1433/master

In batch mode:

mssql-cmd dsn="username:password@host:port/dbname"

example:

mssql-cmd dsn="pan:withdata@192.168.0.102:1433/master"

If you want to hide password

In interactive mode:

mssql-cmd> connect username@host:port/dbname;

example:

mssql-cmd> connect pan@192.168.0.102:1433/master

In batch mode:

mssql-cmd dsn="username@host:port/dbname"

example:

mssql-cmd dsn="pan@192.168.0.102:1433/master"

Disconnect from SQL Server:

mssql-cmd> disconnect;