There are multiple output streams a program can write to, in particular there are the default streams stdout
and stderr
. Other streams can be files, network connections and much more.
The standard stream stderr
is usually used to output error messages and debug info, stdout
is usually used to output the result of a program. What exactly is written to each stream depends on the program.
The stdout
stream has identifier 1, stdout
has identifier 2. The number in front of the >
identifies which stream to redirect. If there is no number given, 1>
is assumed.
You can read more about this here, it should give you some keywords to search.