hi,

i audited the rc based git tools for similar bugs as the last.
i found no more bugs but i wanted to make the error checking
consistent for the tools that use a trivial number of args.

args required:
- git/add:   > 1
- git/merge: 1
- git/push:  0


diff e2e4a46f26ff7268a696a45d82414fb992b648d5 uncommitted
--- a/sys/src/cmd/git/add
+++ b/sys/src/cmd/git/add
@@ -5,7 +5,8 @@
 gitup
 
 flagfmt='r:remove'; args='file ...'
-eval `''{aux/getflags $*} || exec aux/usage
+if(! eval `''{aux/getflags $*} || ~ $#* 0)
+	exec aux/usage
 
 add='tracked'
 del='removed'
@@ -13,8 +14,6 @@
 	add='removed'
 	del='tracked'
 }
-if(~ $#* 0)
-	exec aux/usage
 
 paths=`$nl{cleanname -d $gitrel $* | drop $gitroot}
 if(~ $add tracked)
--- a/sys/src/cmd/git/merge
+++ b/sys/src/cmd/git/merge
@@ -19,9 +19,7 @@
 gitup
 
 flagfmt=''; args='theirs'
-eval `''{aux/getflags $*} || exec aux/usage
-
-if(! ~ $#* 1)
+if (! eval `''{aux/getflags $*} || ! ~ $#* 1)
 	exec aux/usage
 
 theirs=`{git/query $1}
--- a/sys/src/cmd/git/push
+++ b/sys/src/cmd/git/push
@@ -6,8 +6,7 @@
 
 flagfmt='a:pushall, b:branch branch, f:force, d:debug,
          r:remove remove, u:upstream upstream' args=''
-eval `''{aux/getflags $*} || exec aux/usage
-if(! ~ $#* 0)
+if (! eval `''{aux/getflags $*} || ! ~ $#* 0)
 	exec aux/usage
 
 if(~ $pushall 1)