Work around missing tools on MinGW.

egrep cannot be called from the Windows command line.
dd and sum are not available.

t/t1002-read-tree-m-u-2way.sh

@@ -10,6 +10,12 @@ This is identical to t1001, but uses -u to update the work tree as well.
 '
 . ./test-lib.sh
 
+sum ./test-lib.sh >/dev/null 2>&1 || {
+	function sum () {
+		md5sum "$@"
+	}
+}
+
 _x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
 _x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
 compare_change () {

t/t3800-mktag.sh

@@ -15,7 +15,7 @@ check_verify_failure () {
     test_expect_success \
         "$1" \
         'git-mktag <tag.sig 2>message ||
-         egrep -q -f expect.pat message'
+         grep -E -q -f expect.pat message'
 }
 
 ###########################################################

t/t5300-pack-object.sh

@@ -10,12 +10,28 @@ test_description='git-pack-object
 
 TRASH=`pwd`
 
+x4k=xxxxxxxx
+x4k="$x4k$x4k$x4k$x4k$x4k$x4k$x4k$x4k"
+x4k="$x4k$x4k$x4k$x4k$x4k$x4k$x4k$x4k"
+x4k="$x4k$x4k$x4k$x4k$x4k$x4k$x4k$x4k"
+
+corrupt()
+{
+	(
+	read -d "" -n $4 l
+	echo -n "$l"
+	read -d "" -n $3 l
+	echo -n ${x4k:0:$3} | tr x '\0'
+	cat
+	) < $1 > $2
+}
+
 test_expect_success \
     'setup' \
     'rm -f .git/index*
      for i in a b c
      do
-	     dd if=/dev/zero bs=4k count=1 | tr "\\0" $i >$i &&
+	     echo -n "$x4k" | tr x $i >$i &&
 	     git-update-index --add $i || return 1
      done &&
      cat c >d && echo foo >>d && git-update-index --add d &&
@@ -144,8 +160,7 @@ test_expect_success \
 
 test_expect_success \
     'verify-pack catches a corrupted pack signature' \
-    'cp test-1-${packname_1}.pack test-3.pack &&
-     dd if=/dev/zero of=test-3.pack count=1 bs=1 conv=notrunc seek=2 &&
+    'corrupt test-1-${packname_1}.pack test-3.pack 1 2 &&
      if git-verify-pack test-3.idx
      then false
      else :;
@@ -153,8 +168,7 @@ test_expect_success \
 
 test_expect_success \
     'verify-pack catches a corrupted pack version' \
-    'cp test-1-${packname_1}.pack test-3.pack &&
-     dd if=/dev/zero of=test-3.pack count=1 bs=1 conv=notrunc seek=7 &&
+    'corrupt test-1-${packname_1}.pack test-3.pack 1 7 &&
      if git-verify-pack test-3.idx
      then false
      else :;
@@ -162,8 +176,7 @@ test_expect_success \
 
 test_expect_success \
     'verify-pack catches a corrupted type/size of the 1st packed object data' \
-    'cp test-1-${packname_1}.pack test-3.pack &&
-     dd if=/dev/zero of=test-3.pack count=1 bs=1 conv=notrunc seek=12 &&
+    'corrupt test-1-${packname_1}.pack test-3.pack 1 12 &&
      if git-verify-pack test-3.idx
      then false
      else :;
@@ -173,8 +186,7 @@ test_expect_success \
     'verify-pack catches a corrupted sum of the index file itself' \
     'l=`wc -c <test-3.idx` &&
      l=`expr $l - 20` &&
-     cp test-1-${packname_1}.pack test-3.pack &&
-     dd if=/dev/zero of=test-3.idx count=20 bs=1 conv=notrunc seek=$l &&
+     corrupt test-1-${packname_1}.pack test-3.pack 20 $l &&
      if git-verify-pack test-3.pack
      then false
      else :;

t/t5301-sliding-window.sh

@@ -6,6 +6,10 @@
 test_description='mmap sliding window tests'
 . ./test-lib.sh
 
+dd () {
+	perl -e 'print pack("C", rand(256)) foreach 0 .. 32767'
+}
+
 test_expect_success \
     'setup' \
     'rm -f .git/index*