test that the remote system has the cpio command

src/get-facts.sh

@@ -13,6 +13,7 @@ isInstaller=$(if [ "$isNixos" = "y" ] && grep -Eq 'VARIANT_ID="?installer"?' /et
 isContainer=$(if [ "$(has systemd-detect-virt)" = "y" ]; then systemd-detect-virt --container; else echo "none"; fi)
 hasIpv6Only=$(if [ "$(has ip)" = "n" ] || ip r g 1 >/dev/null 2>/dev/null || ! ip -6 r g :: >/dev/null 2>/dev/null; then echo "n"; else echo "y"; fi)
 hasTar=$(has tar)
+hasCpio=$(has cpio)
 hasSudo=$(has sudo)
 hasDoas=$(has doas)
 hasWget=$(has wget)

src/nixos-anywhere.sh

@@ -45,6 +45,7 @@ isInstaller=
 isContainer=
 hasIpv6Only=
 hasTar=
+hasCpio=
 hasSudo=
 hasDoas=
 hasWget=
@@ -434,7 +435,7 @@ importFacts() {
   # shellcheck disable=SC2046
   export $(echo "$filteredFacts" | xargs)
 
-  for var in isOs isArch isKexec isInstaller isContainer hasIpv6Only hasTar hasSudo hasDoas hasWget hasCurl hasSetsid; do
+  for var in isOs isArch isKexec isInstaller isContainer hasIpv6Only hasTar hasCpio hasSudo hasDoas hasWget hasCurl hasSetsid; do
     if [[ -z ${!var} ]]; then
       abort "Failed to retrieve fact $var from host"
     fi
@@ -673,6 +674,10 @@ main() {
     abort "no tar command found, but required to unpack kexec tarball"
   fi
 
+  if [[ ${hasCpio-n} == "n" ]]; then
+    abort "no cpio command found, but required to build the new initrd"
+  fi
+
   if [[ ${hasSetsid-n} == "n" ]]; then
     abort "no setsid command found, but required to run the kexec script under a new session"
   fi