diff --git a/.rubocop.yml b/.rubocop.yml
index fb5cfcd4..3e9d76d6 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -23,6 +23,8 @@
 AllCops:
   SuggestExtensions: false
   NewCops: enable
+  Exclude:
+    - 'venv/**/*'
 
 Layout/EmptyLineAfterGuardClause:
   Enabled: false
diff --git a/Makefile b/Makefile
index 049bbd34..41547c3c 100644
--- a/Makefile
+++ b/Makefile
@@ -63,6 +63,9 @@ define step
 	set -e
 	start=$$(date +%s%N)
 	echo -e "\n\n\n+++ $(1) +++\n"
+	if [ -d "$(LOCAL)/venv" ]; then
+		source "$(LOCAL)/venv/bin/activate"
+	fi
     @bash $(LOCAL)/steps/$(1).sh
 	echo "Finished$$("$${LOCAL}/help/tdiff.sh" "$${start}")"
 endef
diff --git a/installs/install-pip.sh b/installs/install-pip.sh
index 62d279a3..4e061a1f 100755
--- a/installs/install-pip.sh
+++ b/installs/install-pip.sh
@@ -27,7 +27,11 @@ set -o pipefail
 "${LOCAL}/help/assert-tool.sh" python3 --version
 "${LOCAL}/help/assert-tool.sh" pip3 --version
 
-# see https://stackoverflow.com/a/76641565/187141
-rm -f /usr/lib/python3.*/EXTERNALLY-MANAGED
+if [ ! -d "venv" ]; then
+    python3 -m venv venv
+fi
+
+# shellcheck source=/dev/null
+source venv/bin/activate
 
 pip3 install -r "${LOCAL}/requirements.txt"
diff --git a/installs/install-texlive.sh b/installs/install-texlive-base.sh
similarity index 100%
rename from installs/install-texlive.sh
rename to installs/install-texlive-base.sh
diff --git a/steps/env.sh b/steps/env.sh
index 5a47d116..8ebe268c 100755
--- a/steps/env.sh
+++ b/steps/env.sh
@@ -33,7 +33,7 @@ env
 
 bash_version=${BASH_VERSINFO:-0}
 if [ "${bash_version}" -lt 5 ]; then
-    "${SHELL}" -version
+    "${SHELL}" --version
     ps -p $$
     echo "${SHELL} version is older than five: ${bash_version}"
     exit 1
diff --git a/steps/install.sh b/steps/install.sh
index defd8e52..b7acfa7e 100755
--- a/steps/install.sh
+++ b/steps/install.sh
@@ -85,6 +85,16 @@ if ! inkscape --version >/dev/null 2>&1; then
   fi
 fi
 
+if ! xmllint --version >/dev/null 2>&1; then
+  if "${LOCAL}/help/is-linux.sh"; then
+    "${LOCAL}/help/sudo.sh" apt-get install -y libxml2-utils
+  elif "${LOCAL}/help/is-macos.sh"; then
+    "${LOCAL}/help/sudo.sh" --as-user brew install libxml2
+  else
+    "${LOCAL}/help/assert-tool.sh" xmllint --version
+  fi
+fi
+
 find "${LOCAL}/installs" -name 'install-*' | sort | while IFS= read -r i; do
   "${i}"
 done
diff --git a/steps/lint.sh b/steps/lint.sh
index abe4d2f6..d97ede02 100755
--- a/steps/lint.sh
+++ b/steps/lint.sh
@@ -27,11 +27,11 @@ cffconvert --validate
 
 mypy --strict "${LOCAL}/"
 
-flake8 --max-line-length=140 "${LOCAL}/"
+flake8 --max-line-length=140 --exclude venv "${LOCAL}/"
 
 export PYTHONPATH="${PYTHONPATH}:${LOCAL}/pylint_plugins/"
 
-find "${LOCAL}" -type f -name '*.py' -print0 | xargs -0 -n1 pylint --enable-all-extensions --load-plugins=custom_checkers \
+find "${LOCAL}" -type f -name '*.py' -not -path "${LOCAL}/venv/**" -print0 | xargs -0 -n1 pylint --enable-all-extensions --load-plugins=custom_checkers \
     --disable=empty-comment \
     --disable=missing-module-docstring \
     --disable=invalid-name \
@@ -53,7 +53,7 @@ bibcop tex/report.bib
 
 while IFS= read -r sh; do
     shellcheck --shell=bash --severity=style "${sh}"
-done < <(find "$(realpath "${LOCAL}")" -name '*.sh' -type f -not -path "$(realpath "${TARGET}")/**")
+done < <(find "$(realpath "${LOCAL}")" -name '*.sh' -type f -not -path "$(realpath "${TARGET}")/**" -not -path "$(realpath "${LOCAL}")/venv/**")
 
 header="Copyright (c) 2021-$(date +%Y) Yegor Bugayenko"
 failed="false"
@@ -66,6 +66,7 @@ for mask in *.sh *.py *.rb *.yml *.java Makefile; do
     done < <(find "$(realpath "${LOCAL}")" -type f -name "${mask}" \
         -not -path "$(realpath "${TARGET}")/**" \
         -not -path "$(realpath "${LOCAL}")/fixtures/filters/unparseable/**" \
-        -not -path "$(realpath "${LOCAL}")/test-zone/**")
+        -not -path "$(realpath "${LOCAL}")/test-zone/**" \
+        -not -path "$(realpath "${LOCAL}")/venv/**")
 done
 if [[ "${failed}" = "true" ]]; then exit; fi