chore: fix install script

install_perf.sh

@@ -1,7 +1,10 @@
 #!/bin/bash
 
 # If already installed, just return
-[[ -x perf  ]] && return 0
+command -v perf && {
+	echo "perf is already installed."
+	exit 0
+}
 
 [[ "$(whoami)" != "root" ]] && {
 	echo "Expected to run as root"
@@ -11,14 +14,11 @@
 # Under WSL2, perf has to be installed from source
 if  grep --silent 'WSL2' <(uname -r); then
 	echo "WSL detected. perf must be built from source"
-	echo "WSL2 support is WIP and not currently functional"
-	exit 0
-
 	sudo apt-get install flex bison python3-dev liblzma-dev libnuma-dev zlib1g libperl-dev libgtk2.0-dev libslang2-dev systemtap-sdt-dev libelf-dev binutils-dev libbabeltrace-dev libdw-dev libunwind-dev libiberty-dev --yes
 	git clone --depth 1 https://github.com/microsoft/WSL2-Linux-Kernel ~/WSL2-Linux-Kernel
 	make -Wno-error -j8 -C ~/WSL2-Linux-Kernel/tools/perf
 	sudo cp ~/WSL2-Linux-Kernel/tools/perf/perf /usr/local/bin
-	# rm -rf ~/WSL2-Linux-Kernel
+	rm -rf ~/WSL2-Linux-Kernel
 else
 	apt-get install "linux-tools-$(uname -r)" linux-tools-generic -y
 fi