diff --git a/pkgs/build-support/cc-wrapper/add-hardening.sh b/pkgs/build-support/cc-wrapper/add-hardening.sh
index 34358e04194a..b0e39e455ffc 100644
--- a/pkgs/build-support/cc-wrapper/add-hardening.sh
+++ b/pkgs/build-support/cc-wrapper/add-hardening.sh
@@ -16,14 +16,14 @@ do
   hardeningDisableMap[$flag]=1
 done
 
-if [[ -n "${NIX_DEBUG:-}" ]]; then
+if (( "${NIX_DEBUG:-0}" >= 1 )); then
   printf 'HARDENING: disabled flags:' >&2
   (( "${#hardeningDisableMap[@]}" )) && printf ' %q' "${!hardeningDisableMap[@]}" >&2
   echo >&2
 fi
 
 if [[ -z "${hardeningDisableMap[all]:-}" ]]; then
-  if [[ -n "${NIX_DEBUG:-}" ]]; then
+  if (( "${NIX_DEBUG:-0}" >= 1 )); then
     echo 'HARDENING: Is active (not completely disabled with "all" flag)' >&2;
   fi
   for flag in "${hardeningFlags[@]}"
@@ -31,40 +31,40 @@ if [[ -z "${hardeningDisableMap[all]:-}" ]]; then
     if [[ -z "${hardeningDisableMap[$flag]:-}" ]]; then
       case $flag in
         fortify)
-          if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling fortify >&2; fi
+          if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling fortify >&2; fi
           hardeningCFlags+=('-O2' '-D_FORTIFY_SOURCE=2')
           ;;
         stackprotector)
-          if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling stackprotector >&2; fi
+          if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling stackprotector >&2; fi
           hardeningCFlags+=('-fstack-protector-strong' '--param' 'ssp-buffer-size=4')
           ;;
         pie)
-          if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling CFlags -fPIE >&2; fi
+          if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling CFlags -fPIE >&2; fi
           hardeningCFlags+=('-fPIE')
           if [[ ! ("$*" =~ " -shared " || "$*" =~ " -static ") ]]; then
-            if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling LDFlags -pie >&2; fi
+            if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling LDFlags -pie >&2; fi
             hardeningCFlags+=('-pie')
             hardeningLDFlags+=('-pie')
           fi
           ;;
         pic)
-          if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling pic >&2; fi
+          if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling pic >&2; fi
           hardeningCFlags+=('-fPIC')
           ;;
         strictoverflow)
-          if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling strictoverflow >&2; fi
+          if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling strictoverflow >&2; fi
           hardeningCFlags+=('-fno-strict-overflow')
           ;;
         format)
-          if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling format >&2; fi
+          if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling format >&2; fi
           hardeningCFlags+=('-Wformat' '-Wformat-security' '-Werror=format-security')
           ;;
         relro)
-          if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling relro >&2; fi
+          if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling relro >&2; fi
           hardeningLDFlags+=('-z' 'relro')
           ;;
         bindnow)
-          if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling bindnow >&2; fi
+          if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling bindnow >&2; fi
           hardeningLDFlags+=('-z' 'now')
           ;;
         *)
diff --git a/pkgs/build-support/cc-wrapper/cc-wrapper.sh b/pkgs/build-support/cc-wrapper/cc-wrapper.sh
index aacaf196f313..f5bcfc9f9851 100644
--- a/pkgs/build-support/cc-wrapper/cc-wrapper.sh
+++ b/pkgs/build-support/cc-wrapper/cc-wrapper.sh
@@ -161,7 +161,7 @@ if [ "$*" = -v ]; then
 fi
 
 # Optionally print debug info.
-if [ -n "${NIX_DEBUG:-}" ]; then
+if (( "${NIX_DEBUG:-0}" >= 1 )); then
     # Old bash workaround, see ld-wrapper for explanation.
     echo "extra flags before to @prog@:" >&2
     printf "  %q\n" ${extraBefore+"${extraBefore[@]}"}  >&2
diff --git a/pkgs/build-support/cc-wrapper/gnat-wrapper.sh b/pkgs/build-support/cc-wrapper/gnat-wrapper.sh
index f0c922a3d5b4..42df660211b9 100644
--- a/pkgs/build-support/cc-wrapper/gnat-wrapper.sh
+++ b/pkgs/build-support/cc-wrapper/gnat-wrapper.sh
@@ -109,7 +109,7 @@ fi
 #fi
 
 # Optionally print debug info.
-if [ -n "${NIX_DEBUG:-}" ]; then
+if (( "${NIX_DEBUG:-0}" >= 1 )); then
     echo "extra flags before to @prog@:" >&2
     printf "  %q\n" "${extraBefore[@]}"  >&2
     echo "original flags to @prog@:" >&2
diff --git a/pkgs/build-support/cc-wrapper/gnatlink-wrapper.sh b/pkgs/build-support/cc-wrapper/gnatlink-wrapper.sh
index 2de748b5f31e..b0615731b282 100644
--- a/pkgs/build-support/cc-wrapper/gnatlink-wrapper.sh
+++ b/pkgs/build-support/cc-wrapper/gnatlink-wrapper.sh
@@ -24,7 +24,7 @@ extraBefore=()
 #export NIX_@infixSalt@_LDFLAGS_SET=1
 
 # Optionally print debug info.
-if [ -n "${NIX_DEBUG:-}" ]; then
+if (( "${NIX_DEBUG:-0}" >= 1 )); then
     echo "extra flags before to @prog@:" >&2
     printf "  %q\n" "${extraBefore[@]}"  >&2
     echo "original flags to @prog@:" >&2
diff --git a/pkgs/build-support/cc-wrapper/ld-wrapper.sh b/pkgs/build-support/cc-wrapper/ld-wrapper.sh
index a9cc1e3f9e6f..a849df86ef0e 100644
--- a/pkgs/build-support/cc-wrapper/ld-wrapper.sh
+++ b/pkgs/build-support/cc-wrapper/ld-wrapper.sh
@@ -156,7 +156,7 @@ fi
 
 
 # Optionally print debug info.
-if [ -n "${NIX_DEBUG:-}" ]; then
+if (( "${NIX_DEBUG:-0}" >= 1 )); then
     # Old bash workaround, see above.
     echo "extra flags before to @prog@:" >&2
     printf "  %q\n" ${extraBefore+"${extraBefore[@]}"}  >&2
diff --git a/pkgs/build-support/cc-wrapper/utils.sh b/pkgs/build-support/cc-wrapper/utils.sh
index c84a094e26b0..c43c2e12d74a 100644
--- a/pkgs/build-support/cc-wrapper/utils.sh
+++ b/pkgs/build-support/cc-wrapper/utils.sh
@@ -1,5 +1,5 @@
 skip () {
-    if [ -n "${NIX_DEBUG:-}" ]; then
+    if (( "${NIX_DEBUG:-0}" >= 1 )); then
         echo "skipping impure path $1" >&2
     fi
 }
diff --git a/pkgs/stdenv/generic/setup.sh b/pkgs/stdenv/generic/setup.sh
index ce8c3ecef829..524caafc8720 100644
--- a/pkgs/stdenv/generic/setup.sh
+++ b/pkgs/stdenv/generic/setup.sh
@@ -269,7 +269,7 @@ for i in $initialPath; do
     addToSearchPath PATH "$i/bin"
 done
 
-if [ "${NIX_DEBUG:-}" = 1 ]; then
+if (( "${NIX_DEBUG:-0}" >= 1 )); then
     echo "initial path: $PATH"
 fi
 
@@ -429,7 +429,7 @@ fi
 
 
 PATH="${_PATH-}${_PATH:+${PATH:+:}}$PATH"
-if [ "${NIX_DEBUG:-}" = 1 ]; then
+if (( "${NIX_DEBUG:-0}" >= 1 )); then
     echo "final path: $PATH"
 fi
 
@@ -539,7 +539,7 @@ substituteAll() {
     local -a args=()
 
     for varName in $(awk 'BEGIN { for (v in ENVIRON) if (v ~ /^[a-z][a-zA-Z0-9_]*$/) print v }'); do
-        if [ "${NIX_DEBUG:-}" = "1" ]; then
+        if (( "${NIX_DEBUG:-0}" >= 1 )); then
             printf "@%s@ -> %q\n" "${varName}" "${!varName}"
         fi
         args+=("--subst-var" "$varName")