Question: How one can get help about different command in R Language?
Answer: There are many ways to get help about the different command (functions). R has built-in help facility which is similar to man facility in Unix. For beginners to get help with R language, help() function or ? can be used to get help about different commands of R language.

Questions: Provide some examples of getting help with R?
Answer: To get more information on any specific R command (function), for example for getting help about solve(), lm(), plot() etc, write the following commands at R prompt:

> help(solve)
> help(lm)
> help(plot)

Question: Can one get help for special symbols, characters in R Language?
Answer: Yes one can get help for special characters. For example;

> help(“[[“)
> help(“[“)
> help(“^”)
> help(“$”)
> help(“%%”)

Question: What help.start() does?
Answer: The help.start() will launch a web browser that allows the help pages to browsed with hyperlinks. It can be a better way to get help about different functions.

Question: There is help.search() command. What for the purpose it is?
Answer: The help.search() command allows searching for help in various ways. To get what help.search() functions do, write this command at R prompt;

> help(help.search)

Question: Provide some details about help.search() function and also illustrate it by providing some examples?
Answer: The help.search() allows for searching the help system for documentation matching a given character string in the (file) name, alias, title, concept or keyword entries (or any combination thereof), using either fuzzy matching or regular expression matching. Names and titles of the matched help entries are displayed nicely formatted. The examples are:

> help.search(“linear”)
> help.search(“linear models”)
> help.search(“print”)
> help.search(“cat”)

Question: How ? can be used to get help with R language?
Answer: The ? mark can be used to get help with Windows version of R Language. For example;

> ?print
> ?help
> ?”[[“
> ?methods
> ?lm

For further detials, follow the link Getting Help with R Language