What's the difference between tsql and isql?

I saw this in this po开发者_Go百科st,and is really confused

isql is an old CLI tool that I believe Microsoft has deprecated. It looks like from this webpage that tsql is a Linux CLI tool for querying databases and doing diagnostics.

TSql is Microsoft's native Transaction Sql language for SQL Server. http://msdn.microsoft.com/en-us/library/ms189826(SQL.90).aspx

iSql appears to be an old Microsoft utility that allows you to run SQL statements against SQL Server. http://msdn.microsoft.com/en-us/library/aa214007(SQL.80).aspx

SQL Server applications must be using T-SQL statements to communicate with the server, but how your T-SQL is written and run can ultimately impact your server performance.

isql defines the order of the date format as month, date, and year (mm dd yyyy hh:mmAM (or PM)) regardless of the locale environment. To change this default order, use the convert function. isql [-b] [-e] [-F] [-p] [-n] [-v] [-X] [-Y] [-Q]