Basic introductory concepts

[Julius Hamilton]

Hey,

I was wondering if someone could give me a basic overview of the following
part of a makefile:

PREFIX ?= /usr/local

BINDIR = $(DESTDIR)$(PREFIX)/bin

MANDIR = $(DESTDIR)$(PREFIX)/share/man/man1

DOCDIR = $(DESTDIR)$(PREFIX)/share/doc/googler

.PHONY: all install uninstall disable-self-upgrade

all:

install:
 install -m755 -d $(BINDIR)
   install -m755 -d $(MANDIR)
      install -m755 -d $(DOCDIR)
          gzip -c googler.1 > googler.1.gz
               install -m755 googler $(BINDIR)
                     install -m644 googler.1.gz $(MANDIR)
                            install -m644 README.md $(DOCDIR)
                                    rm -f googler.1.gz

uninstall:
 rm -f $(BINDIR)/googler
   rm -f $(MANDIR)/googler.1.gz
      rm -rf $(DOCDIR)



I'm guessing all the capital letters are configuration environmental
variables. I'm not sure what "destdir" and "prefix" are, though, or
".phony".

Then, there are some "install m755" type lines, which I don't know what
precisely they do, perhaps grant file permissions to those directories.

Which part of the documentation discusses these commands?

Thanks very much,
Julius