gyepi

    # redo banana.x

    sh -x banana.x.do banana.x banana XXX > ZZZ

   $1 denotes the target file
   $2 denotes the target file without its extension
   $3 is a temp file: XXX, in this case.

    redo-ifchange grape.y

    CXX=g++

    hello: main.o factorial.o hello.o

    clean:
        rm -rf *o hello

    cat <<EOF > @all.do
    redo hello
    EOF

    cat <<EOF > hello.do
    o='main.o factorial.o hello.o'
    redo-ifchange $o
    g++ $o -o $3
    EOF

    cat <<EOF > default.o.do
    redo-ifchange $2.cpp
    g++ -c $1 -o $3
    EOF

    cat <<EOF > @clean.do
    rm -rf *o hello
    EOF

    cat <<EOF | install -m 0755 /dev/stdin cc
    #!/bin/sh
    g++ -c "\$@"
    EOF

    # sed -i 's/^\(redo-ifchange.\+\)/\1 cc/' *.do
    # sed -i 's}g++ -c}./cc}' *.do

   There was a child went forth every day;
   And the first object he look’d upon, that object he became;
   And that object became part of him for the day, or a certain part of the day, or for many years, or stretching cycles of years.