[PATCH v3 11/13] livepatch/klp-build: add terminal color output

[Joe Lawrence]

Improve the readability of klp-build output by implementing a basic
color scheme.  When the standard output and error are connected to a
terminal, highlight status messages in bold, warnings in yellow, and
errors in red.

Signed-off-by: Joe Lawrence <joe.lawre...@redhat.com>
---
 scripts/livepatch/klp-build | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index 80703ec4d775..fd104ace29e6 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -52,6 +52,15 @@ PATCH_TMP_DIR="$TMP_DIR/tmp"
 
 KLP_DIFF_LOG="$DIFF_DIR/diff.log"
 
+# Terminal output colors
+read -r COLOR_RESET COLOR_BOLD COLOR_ERROR COLOR_WARN <<< ""
+if [[ -t 1 && -t 2 ]]; then
+       COLOR_RESET="\033[0m"
+       COLOR_BOLD="\033[1m"
+       COLOR_ERROR="\033[0;31m"
+       COLOR_WARN="\033[0;33m"
+fi
+
 grep0() {
        # shellcheck disable=SC2317
        command grep "$@" || true
@@ -65,15 +74,15 @@ grep() {
 }
 
 status() {
-       echo "$*"
+       echo -e "${COLOR_BOLD}$*${COLOR_RESET}"
 }
 
 warn() {
-       echo "error: $SCRIPT: $*" >&2
+       echo -e "${COLOR_WARN}warn${COLOR_RESET}: $SCRIPT: $*" >&2
 }
 
 die() {
-       warn "$@"
+       echo -e "${COLOR_ERROR}error${COLOR_RESET}: $SCRIPT: $*" >&2
        exit 1
 }
 
-- 
2.53.0