Restructure arrangement

Restructure arrangement directory structure.

Copy the source trees, but only if they have changed.  This prevents
unnecessary recompilations.

1 files changed, 71 insertions, 0 deletions

diff --git a/m/copy-if-changed.sh b/m/copy-if-changed.sh
new file mode 100755
index 0000000..46356f7
--- /dev/null
+++ b/m/copy-if-changed.sh
@@ -0,0 +1,71 @@
+#! /bin/bash
+
+src=$1
+dst=$2
+
+# Copy tree $src to tree $dst
+
+# Both $src and $dst must be directories.  $dst is created if it does
+# not exist
+
+# All files in the source tree are checked; if they already exist in
+# the destination tree and are identical, they are ignored, otherwise
+# they are copied.  Missing directories are created.
+
+# All files in the destination tree are checked; if they do not exist
+# in the source tree, they are deleted.
+
+if test -z "$src" || test -z "$dst" || test "$src" = "$dst"; then
+    echo "Usage: $0 <src> <dst>"
+    exit 1
+fi
+test -d $src || exit 2
+test -e $dst || mkdir -p $dst
+test -d $dst || exit 3
+
+# Create all directories
+for dir in $(cd $src && find . -type d); do
+    dstdir=$dst/$dir
+    if test -d $dstdir; then
+        : # directory exists; do nothing
+    else
+        echo mkdir $dstdir
+        mkdir -p $dstdir
+    fi
+done
+
+# Delete directories which do not exist
+for dir in $(cd $dst && find . -type d); do
+    srcdir=$src/$dir
+    dstdir=$dst/$dir
+    if test -d $srcdir; then
+        : # directory exists; do nothing
+    else
+        echo rm -rf $dstdir
+        #rm -rf $dstdir
+    fi
+done
+
+# Copy files that differ
+for file in $(cd $src && find . -type f); do
+    srcfile=$src/$file
+    dstfile=$dst/$file
+    if cmp -s $srcfile $dstfile; then
+        : # unchanged; do nothing
+    else
+        echo cp $srcfile
+        cp $srcfile $dstfile
+    fi
+done
+
+# Delete files which do not exist
+for file in $(cd $dst && find . -type f); do
+    srcfile=$src/$file
+    dstfile=$dst/$file
+    if test -e $srcfile; then
+        : # file exists; do nothing
+    else
+        echo rm $dstfile
+        rm $dstfile
+    fi
+done