diff --git a/add b/add
index 81ed505..ff15bb5 100755
--- a/add
+++ b/add
@@ -1,43 +1,29 @@
 #!/usr/bin/python
 
 # update-index.c:add_file_to_cache
-import struct
+import os
 import subprocess
 import sys
 
-# TODO write in C? do all macs have gcc?
-# TODO if cache doesn't exist?
-index = open('.zit/index').read()
-assert index[0:4] == 'DIRC'
-assert struct.unpack('>I', index[4:8]) == (2,)
-num_entries, = struct.unpack('>I', index[8:12])
-entries = []
-i = 12
-for _ in range(num_entries):
-    # ignore inode heuristics, file/symlink bit, permissions
-    i += 40
-    sha1 = index[i:i+20].encode('hex')
-    # just use NUL-terminated?
-    name_length = struct.unpack('>H', index[i+20:i+22])[0] & 0xfff
-    name = index[i+22:i+22+name_length]
-    i += (22 + name_length + 8) / 8 * 8
-    entries.append((name, sha1))
+import index
 
-_, filename = sys.argv
-# TODO handle deleted files?
-sha1 = subprocess.check_output(['hash-object', 'blob', filename]).strip()
-# TODO canonicalize filename?
-entries.append((filename, sha1))
+filenames = subprocess.check_output(['find'] + sys.argv[1:] + ['!', '-type', 'd']).splitlines()
+entries = index.read_index()
+for filename in filenames:
+    entries = [e for e in entries if e[0] != filename]
+    if os.path.exists(filename):
+        if os.path.islink(filename):
+            mode = 0120000
+            with open('.zit/blob.tmp', 'w') as f:
+                f.write(os.readlink(filename))
+            sha1 = subprocess.check_output(['hash-object', 'blob', '.zit/blob.tmp']).strip()
+        else:
+            if os.access(filename, os.X_OK):
+                mode = 0100755
+            else:
+                mode = 0100644
+            sha1 = subprocess.check_output(['hash-object', 'blob', filename]).strip()
+        entries.append((filename, mode, bytearray.fromhex(sha1)))
 entries.sort()
 
-f = open('.zit/index', 'w')
-f.write('DIRC')
-f.write(struct.pack('>II', 2, len(entries)))
-for filename, sha1 in entries:
-    f.write('\0' * 24)
-    f.write(struct.pack('>I', 0b1000000110100100)) # file 644
-    f.write('\0' * 12)
-    f.write(bytearray.fromhex(sha1))
-    f.write(struct.pack('>H', len(filename)))
-    f.write(filename)
-    f.write('\0' * (8 - (len(filename) + 6) % 8))
+index.write_index(entries)
diff --git a/branch b/branch
index 804fd95..ed66566 100755
--- a/branch
+++ b/branch
@@ -8,8 +8,5 @@ if [[ $# -eq 0 ]]; then
 elif [[ $1 == -d ]]; then
     rm -f .zit/refs/heads/$2
 else
-    branchname=$1
-    startpoint=${2-HEAD}
-    rev=$(rev-parse $startpoint)
-    update-ref refs/heads/$branchname $rev
+    update-ref refs/heads/$1 ${2-HEAD}
 fi
diff --git a/cat-file b/cat-file
index a839661..74914cf 100755
--- a/cat-file
+++ b/cat-file
@@ -1,7 +1,6 @@
 #!/usr/bin/python
 
 # git1.0 cat-file.c sha1_file.c:read_object_with_reference
-# TODO follow commit->tree and tag->object
 import sys
 import zlib
 
diff --git a/checkout-index b/checkout-index
index 3c0836a..fa49836 100755
--- a/checkout-index
+++ b/checkout-index
@@ -1,33 +1,20 @@
 #!/usr/bin/python
 
 import os
-import struct
 import subprocess
 
-# TODO dedup w/ write-tree
-index = open('.zit/index').read()
-assert index[0:4] == 'DIRC'
-assert struct.unpack('>I', index[4:8]) == (2,)
-num_entries, = struct.unpack('>I', index[8:12])
-entries = []
-i = 12
-for _ in range(num_entries):
-    # ignore inode heuristics, file/symlink bit, permissions
-    i += 40
-    sha1 = index[i:i+20].encode('hex')
-    # just use NUL-terminated?
-    name_length = struct.unpack('>H', index[i+20:i+22])[0] & 0xfff
-    name = index[i+22:i+22+name_length]
-    i += (22 + name_length + 8) / 8 * 8
-    entries.append((name, sha1))
+import index
 
+entries = index.read_index()
 # entry.c:checkout_entry
-for filename, sha1 in entries:
+for filename, mode, sha1 in entries:
     assert not filename.startswith('/')
     assert '..' not in filename
-    # TODO unlink directories?
-    if os.path.exists(filename):
-        os.unlink(filename)
     subprocess.check_call(['mkdir', '-p', './' + os.path.dirname(filename)])
     # TODO git 1.0 doesn't seem to unlink deleted files
-    subprocess.check_call(['cat-file', 'blob', sha1], stdout=open(filename, 'w'))
+    subprocess.check_call(['cat-file', 'blob', sha1.encode('hex')], stdout=open(filename, 'w'))
+    if mode == 0100755:
+        os.chmod(filename, 0755)
+    elif mode == 0120000:
+        target = open(filename).read()
+        os.symlink(target, filename)
diff --git a/commit b/commit
index 0703122..7dcfc6c 100755
--- a/commit
+++ b/commit
@@ -1,7 +1,8 @@
 #!/bin/bash -e
 
-# TODO unless this is the initial commit
-parents='-p HEAD'
+if [[ -f .zit/$(symbolic-ref HEAD) ]]; then
+    parents='-p HEAD'
+fi
 echo '# write a commit message' > .zit/COMMIT_EDITMSG
 vi .zit/COMMIT_EDITMSG
 tree=$(write-tree)
diff --git a/commit-tree b/commit-tree
index b5f3b2e..3916f87 100755
--- a/commit-tree
+++ b/commit-tree
@@ -1,5 +1,10 @@
 #!/bin/bash -e
 
+export ZIT_AUTHOR_NAME="${ZIT_AUTHOR_NAME-Frank N. Stein}"
+export ZIT_AUTHOR_EMAIL="${ZIT_AUTHOR_EMAIL-eat@brains.com}"
+export ZIT_COMMITTER_NAME="${ZIT_COMMITTER_NAME-$ZIT_AUTHOR_NAME}"
+export ZIT_COMMITTER_EMAIL="${ZIT_COMMITTER_EMAIL-$ZIT_AUTHOR_EMAIL}"
+
 echo tree $1 > .zit/commit.tmp
 shift
 while [[ $1 == -p ]]; do
@@ -7,8 +12,8 @@ while [[ $1 == -p ]]; do
     echo parent $parent >> .zit/commit.tmp
     shift; shift
 done
-echo author "Joe Mou <joe@mou.fo> $(date +'%s %z')" >> .zit/commit.tmp
-echo committer "Joe Mou <joe@mou.fo> $(date +'%s %z')" >> .zit/commit.tmp
+echo author "$ZIT_AUTHOR_NAME <$ZIT_AUTHOR_EMAIL> $(date +'%s %z')" >> .zit/commit.tmp
+echo committer "$ZIT_COMMITTER_NAME <$ZIT_COMMITTER_EMAIL> $(date +'%s %z')" >> .zit/commit.tmp
 echo >> .zit/commit.tmp
 cat >> .zit/commit.tmp
 
diff --git a/get-sha1-basic b/get-sha1-basic
index 1b17ebf..1fb76e4 100755
--- a/get-sha1-basic
+++ b/get-sha1-basic
@@ -4,8 +4,5 @@
 if [[ ${#1} -eq 40 ]]; then
     echo $1
 else
-    cat .zit/$(symbolic-ref $1) 2> /dev/null || \
-        cat .zit/$(symbolic-ref refs/$1) 2> /dev/null || \
-        cat .zit/$(symbolic-ref refs/tags/$1) 2> /dev/null || \
-        cat .zit/$(symbolic-ref refs/heads/$1)
+    cat .zit/$(symbolic-ref $1) 2> /dev/null || cat .zit/$(symbolic-ref refs/heads/$1)
 fi
diff --git a/index.py b/index.py
new file mode 100644
index 0000000..ed46fa0
--- /dev/null
+++ b/index.py
@@ -0,0 +1,36 @@
+import os
+import struct
+
+def write_index(entries):
+    f = open('.zit/index', 'w')
+    f.write('DIRC')
+    f.write(struct.pack('>II', 2, len(entries)))
+    for filename, mode, rawsha1 in entries:
+        f.write('\0' * 24)
+        f.write(struct.pack('>I', mode))
+        f.write('\0' * 12)
+        f.write(rawsha1)
+        f.write(struct.pack('>H', len(filename)))
+        f.write(filename)
+        f.write('\0' * (8 - (len(filename) + 6) % 8))
+
+def read_index():
+    if not os.path.exists('.zit/index'):
+        return []
+    index = open('.zit/index').read()
+    assert index[0:4] == 'DIRC'
+    assert struct.unpack('>I', index[4:8]) == (2,)
+    num_entries, = struct.unpack('>I', index[8:12])
+    i = 12
+    entries = []
+    for _ in range(num_entries):
+        # ignore inode heuristics
+        mode, = struct.unpack('>I', index[i+24:i+28])
+        i += 40
+        rawsha1 = index[i:i+20]
+        # just use NUL-terminated?
+        filename_length = struct.unpack('>H', index[i+20:i+22])[0] & 0xfff
+        filename = index[i+22:i+22+filename_length]
+        i += (22 + filename_length + 8) / 8 * 8
+        entries.append((filename, mode, rawsha1))
+    return entries
diff --git a/read-tree b/read-tree
index 2b1955a..cb29ad0 100755
--- a/read-tree
+++ b/read-tree
@@ -5,27 +5,18 @@ import struct
 import subprocess
 import sys
 
+import index
+
 _, tree_sha1 = sys.argv
 tree = subprocess.check_output(['cat-file', 'tree', tree_sha1])
 entries = []
 while tree:
     header, rest = tree.split('\0', 1)
-    flags, filename = header.split(' ', 1)
+    mode, filename = header.split(' ', 1)
     rawsha1 = rest[:20]
     tree = rest[20:]
     # TODO handle directories
-    if flags != '040000':
-        entries.append((flags, filename, rawsha1))
+    if mode != '040000':
+        entries.append((filename, int(mode, 8), rawsha1))
 
-# TODO dedup with add. this handles flags
-f = open('.zit/index', 'w')
-f.write('DIRC')
-f.write(struct.pack('>II', 2, len(entries)))
-for flags, filename, rawsha1 in entries:
-    f.write('\0' * 24)
-    f.write(struct.pack('>I', int(flags, 8)))
-    f.write('\0' * 12)
-    f.write(rawsha1)
-    f.write(struct.pack('>H', len(filename)))
-    f.write(filename)
-    f.write('\0' * (8 - (len(filename) + 6) % 8))
+index.write_index(entries)
diff --git a/rev-parse b/rev-parse
index 33ac383..1c4d37b 100755
--- a/rev-parse
+++ b/rev-parse
@@ -27,7 +27,7 @@ def get_sha1(name):
                 return sha1
             elif actual_type == 'commit':
                 assert int(length) == len(contents)
-                tree = next(line for line in contents.split('\n')
+                tree = next(line for line in contents.splitlines()
                             if line.startswith('tree '))
                 name = tree.split(' ')[1]
             # TODO deref tags?
diff --git a/update-ref b/update-ref
index 605639d..75f6743 100755
--- a/update-ref
+++ b/update-ref
@@ -2,6 +2,5 @@
 
 path=.zit/$(symbolic-ref $1)
 sha1=$(rev-parse $2)
-# TODO initialize directory structure instead?
 mkdir -p $(dirname $path)
 echo $sha1 > $path
diff --git a/write-tree b/write-tree
index 63f6ac7..ccb6fc4 100755
--- a/write-tree
+++ b/write-tree
@@ -1,36 +1,18 @@
 #!/usr/bin/python
 
 # write-tree.c
-import struct
 import subprocess
-import sys
 
-# TODO write in C? do all macs have gcc?
-# TODO if cache doesn't exist?
-index = open('.zit/index').read()
-assert index[0:4] == 'DIRC'
-assert struct.unpack('>I', index[4:8]) == (2,)
-num_entries, = struct.unpack('>I', index[8:12])
-entries = []
-i = 12
-for _ in range(num_entries):
-    # ignore inode heuristics, file/symlink bit, permissions
-    i += 40
-    sha1 = index[i:i+20].encode('hex')
-    # just use NUL-terminated?
-    name_length = struct.unpack('>H', index[i+20:i+22])[0] & 0xfff
-    name = index[i+22:i+22+name_length]
-    i += (22 + name_length + 8) / 8 * 8
-    entries.append((name, sha1))
+import index
 
+entries = index.read_index()
 # TODO write directories recursively? groupby?
 f = open('.zit/tree.tmp', 'w')
-for filename, sha1 in entries:
-    # TODO directories and file 755
-    f.write('100644 ') # file 644
+for filename, mode, rawsha1 in entries:
+    f.write('{:o} '.format(mode))
     f.write(filename)
     f.write('\0')
-    f.write(bytearray.fromhex(sha1))
+    f.write(rawsha1)
 f.close()
 
 subprocess.check_call(['hash-object', 'tree', '.zit/tree.tmp'])
diff --git a/zit b/zit
index 8fd538e..5531c4d 100755
--- a/zit
+++ b/zit
@@ -1,4 +1,4 @@
 #!/bin/bash -e
 
-export PATH="${BASH_SOURCE%/*}:$PATH"
+export PATH="$(cd "${BASH_SOURCE%/*}"; echo "$PWD"):$PATH"
 exec "$@"