268ef4d3d0
In shell code like:
test -z $foo
test -n $foo
that does not quote its arguments, it's easy to think that
it is actually looking at the contents of $foo in each case.
But if $foo is empty, then "test" does not see any argument
at all! The results are quite subtle.
POSIX specifies that test's behavior depends on the number
of arguments it sees, and if $foo is empty, it sees only
one. The behavior in this case is:
1 argument: Exit true (0) if $1 is not null; otherwise,
exit false.
So in the "-z $foo" case, if $foo is empty, then we check
that "-z" is non-null, and it returns success. Which happens
to match what we expected. But for "-n $foo", if $foo is
empty, we'll see that "-n" is non-null and still return
success. That's the opposite of what we intended!
Furthermore, if $foo contains whitespace, we'll end up with
more than 2 arguments. The results in this case are
generally unspecified (unless the first part of $foo happens
to be a valid binary operator, in which case the results are
specified but certainly not what we intended).
And on top of this, even though "test -z $foo" _should_ work
for the empty case, some older shells (reportedly ksh88)
complain about the missing argument.
So let's make sure we consistently quote our variable
arguments to "test". After this patch, the results of:
git grep 'test -[zn] [^"]'
are empty.
Reported-by: Armin Kunaschik <megabreit@googlemail.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git - fast, scalable, distributed revision control system
Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.
Git is an Open Source project covered by the GNU General Public License version 2 (some parts of it are under different licenses, compatible with the GPLv2). It was originally written by Linus Torvalds with help of a group of hackers around the net.
Please read the file INSTALL for installation instructions.
Many Git online resources are accessible from http://git-scm.com/ including full documentation and Git related tools.
See Documentation/gittutorial.txt to get started, then see Documentation/giteveryday.txt for a useful minimum set of commands, and Documentation/git-commandname.txt for documentation of each command. If git has been correctly installed, then the tutorial can also be read with "man gittutorial" or "git help tutorial", and the documentation of each command with "man git-commandname" or "git help commandname".
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The name "git" was given by Linus Torvalds when he wrote the very first version. He described the tool as "the stupid content tracker" and the name as (depending on your mood):
- random three-letter combination that is pronounceable, and not actually used by any common UNIX command. The fact that it is a mispronunciation of "get" may or may not be relevant.
- stupid. contemptible and despicable. simple. Take your pick from the dictionary of slang.
- "global information tracker": you're in a good mood, and it actually works for you. Angels sing, and a light suddenly fills the room.
- "goddamn idiotic truckload of sh*t": when it breaks