diff --git a/system/etsh/doinst.sh b/system/etsh/doinst.sh
new file mode 100644
index 0000000000..2e23c07769
--- /dev/null
+++ b/system/etsh/doinst.sh
@@ -0,0 +1 @@
+grep -q '^/bin/etsh$' etc/shells 2>/dev/null || echo "/bin/etsh" >> etc/shells
diff --git a/system/etsh/etsh.SlackBuild b/system/etsh/etsh.SlackBuild
index c43a73efd2..a759ec07e7 100644
--- a/system/etsh/etsh.SlackBuild
+++ b/system/etsh/etsh.SlackBuild
@@ -18,6 +18,9 @@
 # The name means "Extended Thompson Shell", it's nothing to do with
 # phoning home...
 
+# 20220507 bkw, BUILD=2:
+# - add doinst.sh: add /bin/etsh to /etc/shells, but not /bin/tsh
+#   per upstream's recommendation.
 # 20191201 bkw: updated for v5.4.0.
 # 20180902 bkw: updated for v5.3.1.
 
@@ -27,7 +30,7 @@ PRGNAM=etsh
 VERSION=${VERSION:-5.4.0}    # main etsh version
 V6S_VER=${V6S_VER:-20180109} # v6scripts version
 LT_VER=${LT_VER:-20180115}   # looptest  version
-BUILD=${BUILD:-1}
+BUILD=${BUILD:-2}
 TAG=${TAG:-_SBo}
 PKGTYPE=${PKGTYPE:-tgz}
 
@@ -102,6 +105,7 @@ cat $CWD/$PRGNAM.SlackBuild > $DOCDIR/$PRGNAM.SlackBuild
 
 mkdir -p $PKG/install
 cat $CWD/slack-desc > $PKG/install/slack-desc
+cat $CWD/doinst.sh > $PKG/install/doinst.sh
 
 cd $PKG
 /sbin/makepkg -l y -c n $OUTPUT/$PRGNAM-$VERSION-$ARCH-$BUILD$TAG.$PKGTYPE