Address issues reported by pre-commit for pip plugin.

plugins/available/pip.plugin.bash

@@ -2,23 +2,23 @@ cite about-plugin
 about-plugin 'pip upgrade/uninstall all packages'
 
 pip-upgrade-all() {
-  local outdated_packages="$(pip list --outdated --format=freeze | grep -v '^\-e' | cut -d = -f 1)"
+	local outdated_packages="$(pip list --outdated --format=freeze | grep -v '^\-e' | cut -d = -f 1)"
-  if [ -z $outdated_packages ]; then
+	if [ -z "$outdated_packages" ]; then
-    echo "pip: everything is up to date."
+		echo "pip: everything is up to date."
-  else
+	else
-    for package in $outdated_packages; do
+		for package in $outdated_packages; do
-      pip install --user -U $package
+			pip install --user -U "$package"
-    done
+		done
-  fi
+	fi
 }
 
 pip-uninstall-all() {
-  local installed_packages="$(pip list --user --format=freeze | grep -v '^\-e' | cut -d = -f 1)"
+	local installed_packages="$(pip list --user --format=freeze | grep -v '^\-e' | cut -d = -f 1)"
-  if [ -z $installed_packages ]; then
+	if [ -z "$installed_packages" ]; then
-    echo "pip: nothing has been installed."
+		echo "pip: nothing has been installed."
-  else
+	else
-    for package in $installed_packages; do
+		for package in $installed_packages; do
-      pip uninstall -y $package
+			pip uninstall -y "$package"
-    done
+		done
-  fi
+	fi
 }