Check for existence of process files

detect_environment.sh

@@ -14,7 +14,7 @@ arm* | aarch64)
 esac
 
 # Check if running in Docker.
-if [ -f /.dockerenv ] || grep -qa docker /proc/1/cgroup; then
+if [ -f /.dockerenv ] || { [ -f /proc/1/cgroup ] && grep -qa docker /proc/1/cgroup; }; then
 	is_docker=true
 fi
 
@@ -24,7 +24,7 @@ if [ "$(uname)" = "Darwin" ]; then
 fi
 
 # Check if running on WSL.
-if grep -qi microsoft /proc/sys/kernel/osrelease; then
+if [ -f /proc/sys/kernel/osrelease ] && grep -qi microsoft /proc/sys/kernel/osrelease; then
 	is_wsl=true
 fi