diff --git a/libexec/sourcezap/commands/sourcezap-install b/libexec/sourcezap/commands/sourcezap-install
index 5ff16f8..a36fc85 100755
--- a/libexec/sourcezap/commands/sourcezap-install
+++ b/libexec/sourcezap/commands/sourcezap-install
@@ -5,7 +5,6 @@ set -e
 # variables
 localbase=${LOCALBASE:-$(realpath "$(dirname "$0")"/../../..)}
 libexec="${localbase}"/libexec/sourcezap
-mode=u=rwX,g=rX,o=
 git="${libexec}"/utils/git/run
 gitdir=$1
 installdir=$2
@@ -16,60 +15,6 @@ revfile=$3
 # shellcheck source=/dev/null
 . "${libexec}"/functions/print.sh
 
-perform_update()
-{
-    # shellcheck disable=SC3043
-    local rev add del \
-          target parent parents
-    rev=$(cat "${revfile}")
-    add=$("${libexec}"/utils/git/get-changed-files "${gitdir}" "${rev}")
-    del=$("${libexec}"/utils/git/get-removed-files "${gitdir}" "${rev}")
-    for file in ${del}; do
-        target="${installdir}/${file}"
-        parent=$(dirname "${target}")
-        echo "rm ${target}"
-        rm -f "${target}"
-        find "${parent}" -type d -maxdepth 0 -empty -delete
-    done
-    for file in ${add}; do
-        target="${installdir}/${file}"
-        parent=$(dirname "${target}")
-        parents=""
-        while [ ! -e "${parent}" ]; do
-            parents="${parent} ${parents}"
-            parent=$(dirname "${parent}")
-        done
-        for dir in ${parents}; do
-            run_install "-d" "${dir}"
-        done
-        run_install "${file}" "${target}"
-    done
-}
-
-perform_install()
-{
-    find -s . \
-        -maxdepth 1 \
-        ! -name "." \
-        ! -name ".git" \
-        ! -name ".github" \
-        ! -name ".gitignore" \
-        ! -name ".gitattributes" \
-        ! -name ".git-blame-ignore-revs" \
-        ! -name ".cirrus-ci" \
-        ! -name ".cirrus.yml" \
-        ! -name ".gitignore" \
-        ! -name ".arclint" \
-        ! -name ".arcconfig" \
-        -exec cp -Rpv {} "${installdir}" \;
-    chown -Rv root "${installdir}"
-}
-
-run_install()
-{
-    install -o root -g _sourcezap -m "${mode}" -v "$@"
-}
-
 ##
 # main
 if [ "$(id -u)" != "0" ]; then
@@ -77,14 +22,34 @@ if [ "$(id -u)" != "0" ]; then
     exit 1
 fi
 
-umask "${mode}"
 cd "${gitdir}"
-run_install "-d" "${installdir}"
-chmod ${mode} "${installdir}"
 if [ -e "${revfile}" ]; then
-    perform_update
+    ##
+    # install update
+    rev=$(cat "${revfile}")
+    "${libexec}"/utils/install/run -d "${installdir}"
+    "${libexec}"/utils/install/update-deleted-files "${gitdir}" "${installdir}" "${rev}"
+    "${libexec}"/utils/install/update-changed-files "${gitdir}" "${installdir}" "${rev}"
 else
-    perform_install
+    ##
+    # install from scratch
+    umask u=rwx,g=rx,o=
+    "${libexec}"/utils/install/run -d "${installdir}"
+    find -s . \
+         -maxdepth 1 \
+         ! -name "." \
+         ! -name ".git" \
+         ! -name ".github" \
+         ! -name ".gitignore" \
+         ! -name ".gitattributes" \
+         ! -name ".git-blame-ignore-revs" \
+         ! -name ".cirrus-ci" \
+         ! -name ".cirrus.yml" \
+         ! -name ".gitignore" \
+         ! -name ".arclint" \
+         ! -name ".arcconfig" \
+         -exec cp -Rpv {} "${installdir}" \;
+    chown -Rv root "${installdir}"
 fi
 "${git}" rev-parse HEAD > "${revfile}"
 printok "install complete"
diff --git a/libexec/sourcezap/utils/install/run b/libexec/sourcezap/utils/install/run
new file mode 100755
index 0000000..215d34c
--- /dev/null
+++ b/libexec/sourcezap/utils/install/run
@@ -0,0 +1,14 @@
+#!/bin/sh
+set -e
+
+##
+# variables
+mode=u=rwX,g=rX,o=
+
+##
+# main
+install -o root \
+        -g _sourcezap \
+        -m "${mode}" \
+        -v \
+        "${@}"
diff --git a/libexec/sourcezap/utils/install/update-changed-files b/libexec/sourcezap/utils/install/update-changed-files
new file mode 100755
index 0000000..51da754
--- /dev/null
+++ b/libexec/sourcezap/utils/install/update-changed-files
@@ -0,0 +1,28 @@
+#!/bin/sh
+set -e
+
+##
+# variables
+localbase=${LOCALBASE:-$(realpath "$(dirname "$0")"/../../../..)}
+libexec="${localbase}"/libexec/sourcezap
+gitdir=$1
+installdir=$2
+rev=$3
+
+##
+# main
+cd "${gitdir}"
+files=$("${libexec}"/utils/git/get-changed-files "${gitdir}" "${rev}")
+for file in ${files}; do
+    target="${installdir}/${file}"
+    parent=$(dirname "${target}")
+    parents=""
+    while [ ! -e "${parent}" ]; do
+        parents="${parent} ${parents}"
+        parent=$(dirname "${parent}")
+    done
+    for dir in ${parents}; do
+        "${libexec}"/utils/install/run -d "${dir}"
+    done
+    "${libexec}"/utils/install/run "${file}" "${target}"
+done
diff --git a/libexec/sourcezap/utils/install/update-deleted-files b/libexec/sourcezap/utils/install/update-deleted-files
new file mode 100755
index 0000000..71ec800
--- /dev/null
+++ b/libexec/sourcezap/utils/install/update-deleted-files
@@ -0,0 +1,22 @@
+#!/bin/sh
+set -e
+
+##
+# variables
+localbase=${LOCALBASE:-$(realpath "$(dirname "$0")"/../../../..)}
+libexec="${localbase}"/libexec/sourcezap
+gitdir=$1
+installdir=$2
+rev=$3
+
+##
+# main
+cd "${gitdir}"
+files=$("${libexec}"/utils/git/get-removed-files "${gitdir}" "${rev}")
+for file in ${files}; do
+    target="${installdir}/${file}"
+    parent=$(dirname "${target}")
+    echo "rm ${target}"
+    rm -f "${target}"
+    find "${parent}" -type d -maxdepth 0 -empty -delete
+done
diff --git a/share/sourcezap/CHANGELOG b/share/sourcezap/CHANGELOG
index b418d37..77aa9f2 100644
--- a/share/sourcezap/CHANGELOG
+++ b/share/sourcezap/CHANGELOG
@@ -1,13 +1,17 @@
 * vNEXT
 
+** Break up 'sourcezap-install' into multiple files
+'libexec/sourcezap/utils/install/' contains files that cover both
+a fresh install and applying an update
+
 ** Add 'setup/setup-doas' improvements
 More likely to do what's expected, but blind spots still exist
 
 ** Add 'sourcezap setup', 'sourcezap teardown'
 Replaces and enhances 'setup-sourcezap'
 
-** Add libexec/sourcezap/commands/sourcezap-sh
-Runs /bin/sh within /home/_sourcezap/src/ as the '_sourcezap' user
+** Add 'libexec/sourcezap/commands/sourcezap-sh'
+Runs '/bin/sh' within '/home/_sourcezap/src/' as the '_sourcezap' user
 
 * v1.0.0