diff --git a/README.md b/README.md
index 4a85148..84e1275 100644
--- a/README.md
+++ b/README.md
@@ -273,12 +273,13 @@ zlib
 
 ## Configuration
 
-The compilation of some extensions may be fine-tuned to better fit your needs by using environment variables:
+You can configure the behavior of the script, as well as fine-tune some extensions in order fit your needs, by using environment variables:
 
 | Extension | Environment variable | Description |
 |---|---|---|
-| lzf | IPE_LZF_BETTERCOMPRESSION=1 | By default `install-php-extensions` compiles the `lzf` extension to prefer speed over size; you can use this environment variable to compile it preferring size over speed  |
-| event | IPE_EVENT_NAMESPACE=... | By default the `event` classes are defined in the root namespace. You can use this environment variable to specify a custom namespace |
+| | `IPE_KEEP_SYSPKG_CACHE=1` | By default the script will clear the apt/apk/pear cache in order to save disk space. You can disable it by setting this environment variable |
+| lzf | `IPE_LZF_BETTERCOMPRESSION=1` | By default `install-php-extensions` compiles the `lzf` extension to prefer speed over size; you can use this environment variable to compile it preferring size over speed  |
+| event | `IPE_EVENT_NAMESPACE=`... | By default the `event` classes are defined in the root namespace. You can use this environment variable to specify a custom namespace |
 
 ## Special requirements
 
diff --git a/install-php-extensions b/install-php-extensions
index e41e655..9f4e474 100755
--- a/install-php-extensions
+++ b/install-php-extensions
@@ -2725,20 +2725,25 @@ cleanup() {
 				;;
 		esac
 	fi
-	case "$DISTRO" in
-		alpine)
-			rm -rf /var/cache/apk/*
-			;;
-		debian)
-			rm -rf /var/lib/apt/lists/*
-			;;
-	esac
 	docker-php-source delete
-	rm -rf /tmp/pear
 	rm -rf /tmp/src
 	rm -rf /tmp/pickle
 	rm -rf /tmp/pickle.tmp
 	rm -rf "$CONFIGURE_FILE"
+	case "${IPE_KEEP_SYSPKG_CACHE:-}" in
+		1 | y* | Y*) ;;
+		*)
+			case "$DISTRO" in
+				alpine)
+					rm -rf /var/cache/apk/*
+					;;
+				debian)
+					rm -rf /var/lib/apt/lists/*
+					;;
+			esac
+			rm -rf /tmp/pear
+			;;
+	esac
 }
 
 resetIFS