diff --git a/contrib/install-pysolfc.sh b/contrib/install-pysolfc.sh
index ed587d7f..8fa52213 100755
--- a/contrib/install-pysolfc.sh
+++ b/contrib/install-pysolfc.sh
@@ -1,14 +1,15 @@
 #! /bin/sh -Cefu
 
 : ${PKGTREE:=/usr/local/packages/PySolFC}
-PIP=$(printf '%s/env/bin/pip install --no-binary :all: ' $PKGTREE)
-PYPROG=$(printf '%s/env/bin/python' $PKGTREE)
-VERSION=$(env PYTHONPATH=`pwd` $PYPROG -c 'from pysollib.settings import VERSION ; print(VERSION)' )
-XZBALL=$(printf 'dist/PySolFC-%s.tar.xz' $VERSION)
-REQS='six random2 pillow'
+PIP="$(printf '%s/env/bin/pip install --no-binary :all: ' "$PKGTREE")"
+PYPROG="$(printf '%s/env/bin/python' "$PKGTREE")"
+VERSION="$(env PYTHONPATH=`pwd` "$PYPROG" -c 'from pysollib.settings import VERSION ; print(VERSION)')"
+XZBALL="$(printf 'dist/PySolFC-%s.tar.xz' "$VERSION")"
+reqs='six random2 pillow'
 
 make dist
-for req in $REQS ; do
-    $PIP $req
+for req in $reqs
+do
+    "$PIP" "$req"
 done
-$PIP --upgrade $XZBALL
+"$PIP" --upgrade "$XZBALL"