What do the parentheses and number after a Linux command or C function mean?
I just installed FreeBSD 8.2 using a DVD ISO and I'm a first time user of FreeBSD. I wonder why the documentation uses parentheses and numbers when describing certain functions. For example, here's a portion of the text from this documentation:
Unpack the software from its distribution format (typically a tarball compressed with compress(1), gzip(1), or bzip2(1)).
Notice the words compress, gzip and bzip2. Why do they put a parenthesis and a number after it? Even in the detail page of each function, they also use a parenthesis and a number such as:
COMPRESS(1) FreeBSD General Commands Manual COMPRESS(1) NAME compress, uncompress -- compress and expand data SYNOPSIS compress [-fv] [-b bits] [file ...] compress -c [-b bits] [file] uncompress [-f] [file ...] uncompress -c [file]
Is there any special meaning or notation about the usage of parenthesis and a number in it?