diff --git a/roles/common/files/pip_check_requirements_upgrades.sh b/roles/common/files/pip_check_requirements_upgrades.sh
index d45980b2f6b7960a65617d2c92292f393bb3017a..18ee71075fb93e0dede7a905dd88819107ba29b7 100755
--- a/roles/common/files/pip_check_requirements_upgrades.sh
+++ b/roles/common/files/pip_check_requirements_upgrades.sh
@@ -145,19 +145,6 @@ function error() {
     echo -e "${_text_bold}${_text_red}[ERROR]${_text_reset}" "$@" >&2
 }
 
-# Clean-up command for temporary files.
-function on_exit() {
-    debug "Cleaning-up temporary file: $tmp_current"
-    [[ -f $tmp_current ]] && rm "$tmp_current"
-
-    debug "Cleaning-up temporary file: $tmp_new"
-    [[ -f $tmp_new ]] && rm "$tmp_new"
-
-    debug "Cleaning-up temporary file: $tmp_new_sorted"
-    [[ -f $tmp_new_sorted ]] && rm "$tmp_new_sorted"
-}
-trap on_exit EXIT
-
 # Define error codes.
 SUCCESS=0
 ERROR_ARGUMENTS=1
@@ -223,12 +210,6 @@ if ! which pip-compile >/dev/null 2>&1; then
     exit "$ERROR_PIP_TOOLS_MISSING"
 fi
 
-# Create temporary files where files where "normalised" outputs will be
-# stored.
-tmp_current=$(mktemp)
-tmp_new=$(mktemp)
-tmp_new_sorted=$(mktemp)
-
 # Process each environment.
 for environment in "$config_dir"/*; do
     # Empty directory.
@@ -252,21 +233,32 @@ for environment in "$config_dir"/*; do
 	    continue
 	fi
 
-	# Deploy the existing requirements file and the new one.
-	sed -e 's/[[:blank:]]*#.*//' "$req_txt" | grep -v "^$" | sort -u > "$tmp_current" 
-	if ! pip-compile --quiet --allow-unsafe --no-header --no-annotate --no-index --output-file "$tmp_new" --upgrade "$req_in"; then
-	    error "Failed while running pip-compile command against (see error stack trace above): $req_in"
+        # Clean up the existing requirements file to contain only
+        # package versioning information.
+        current=$(sed -e 's/[[:blank:]]*#.*//' "$req_txt" | grep -v "^$" | sort -u)
+
+        # Calculate up-to-date requirements.
+        new=$(pip-compile --quiet --allow-unsafe --no-header --no-annotate --no-index --output-file - --upgrade "$req_in")
+        result="$?"
+        if [[ $result != 0 ]]; then
+             error "Failed while running pip-compile command against (see error stack trace above): $req_in"
 	    continue
-	fi
+        fi
 
-        # Sort the new requirements file.
-        sed -e 's/[[:blank:]]*#.*//' "$tmp_new" | grep -v "^$" | sort -u > "$tmp_new_sorted"
+        # Clean up the new requirements to contain only package
+        # versioning information.
+        new=$(echo "$new" | sed -e 's/[[:blank:]]*#.*//' | grep -v "^$" | sort -u)
 
-        debug "Current requirements:\n$(cat "$tmp_current")"
-        debug "New requirements:\n$(cat "$tmp_new_sorted")"
+        debug "Current requirements:\n$(echo "$current")"
+        debug "New requirements:\n$(echo "$new")"
 
 	# Run diff, storing the output and result.
-	diff=$(diff -u "$tmp_current" "$tmp_new_sorted")
+        # This is using Bash process substitution, which helps avoid
+        # creating and keeping track of temporary files (since diff
+        # must be fed with two input files). E.g. the <() will
+        # essentially be path to a Bash-created/managed temporary
+        # file.
+	diff=$(diff -u <(echo "$current") <(echo "$new"))
 	result="$?"
 
 	# Show warning about available updates.