Linux – man gcc not working

man 3 ls will only show you a man page for ls in section 3 of the manual. Section 3 covers library functions; since there's (probably) no library function named ls, it won't find anything.

The man command without a section number searches the sections in a predefined order that I don't remember, but it's likely to be close to numerical order starting at 1. So man ls will find the ls man page in section 1, which covers user commands.

The sections (on my Ubuntu system) are:

   1   Executable programs or shell commands
   2   System calls (functions provided by the kernel)
   3   Library calls (functions within program libraries)
   4   Special files (usually found in /dev)
   5   File formats and conventions eg /etc/passwd
   6   Games
   7   Miscellaneous (including macro packages and conventions), e.g. man(7), groff(7)
   8   System administration commands (usually only for root)
   9   Kernel routines [Non standard]

Specifying the section can be useful for things that exist with the same name in more than one section. For example, man printf will show you the man page for the printf user command in section 1; to see the man page for the printf function, use man 3 printf. You'll often see these man pages referred to as printf(1) and printf(3), respectively.

Stealing Borrowing from abernert's answer, it's common to see a user command (section 1) that's a wrapper for a system call (section 2) or library call (section 3) with the same name; chown and chmod are good examples of this.

OpenSSL is often considered a core package as it is used by a number of others to provide security features, and I would recommend against hand-rolling core packages unless you have a particularly good understanding of the potential repercussions. If you do hand-roll it I would recommend installing over the provided package, instead installing it into /usr/local or even your user home and compiling what-ever you need that needs the updated library where to find it as pat of their build procedure - this was you do not disrupt other binary packages that depend upon openssl. If you hand-roll openssl you will need to rebuild it each time an update is released (and may need to rebuild other dependent packes each time too depending on the changes).

Would it be possible to instead update your Debian installation to the latest Stable instead? That includes v1.0.1e by default (see http://packages.debian.org/search?suite=wheezy&searchon=names&keywords=openssl) and means you get future updates with no extra effort.