Allow disabling colors via NO_COLOR environment variable

README.md

@@ -61,6 +61,7 @@ For more information on SemVer, please visit [http://semver.org](http://semver.o
 
 ### v1.2.0 (Unreleased)
 
+- Allow disabling colors via `NO_COLOR` environment variable
 - Enable errexit, nounset and pipefail at the top
 - More refined colors (thanks @arathai)
 - Add Changelog

main.sh

@@ -39,6 +39,7 @@ set -o pipefail
 
 # Environment variables and their defaults
 LOG_LEVEL="${LOG_LEVEL:-6}" # 7 = debug -> 0 = emergency
+NO_COLOR="${NO_COLOR:-}"    # true = disable color. otherwise autodetected
 
 # Commandline options. This defines the usage page, and is used to parse cli
 # opts & defaults from. The parsing is unforgiving so be precise in your syntax
@@ -80,7 +81,7 @@ function _fmt ()      {
 
   local color="${!colorvar:-$color_error}"
   local color_reset="\x1b[0m"
-  if [[ "${TERM:-}" != "xterm"* ]] || [ -t 1 ]; then
+  if [ "${NO_COLOR}" = "true" ] || [[ "${TERM:-}" != "xterm"* ]] || [ -t 1 ]; then
     # Don't use colors on pipes or non-recognized terminals
     color=""; color_reset=""
   fi

test/fixture/nocolor.exitcode

@@ -0,0 +1 @@
+1

test/fixture/nocolor.stdio

@@ -0,0 +1,19 @@
+B3BP:STDIO_REPLACE_DATETIMES
+{datetime} UTC [    debug] cli arg arg_f = () -> {tmpdir}/x
+{datetime} UTC [     info] __file: {root}/main.sh
+{datetime} UTC [     info] __dir: {root}
+{datetime} UTC [     info] __base: main
+{datetime} UTC [     info] __os: {os}
+{datetime} UTC [     info] arg_f: {tmpdir}/x
+{datetime} UTC [     info] arg_d: 0
+{datetime} UTC [     info] arg_v: 0
+{datetime} UTC [     info] arg_h: 0
+{datetime} UTC [    debug] Info useful to developers for debugging the application, not useful during operations.
+{datetime} UTC [     info] Normal operational messages - may be harvested for reporting, measuring throughput, etc. - no action required.
+{datetime} UTC [   notice] Events that are unusual but not error conditions - might be summarized in an email to developers or admins to spot potential problems - no immediate action required.
+{datetime} UTC [  warning] Warning messages, not an error, but indication that an error will occur if action is not taken, e.g. file system 85% full - each item must be resolved within a given time. This is a debug message
+{datetime} UTC [    error] Non-urgent failures, these should be relayed to developers or admins; each item must be resolved within a given time.
+{datetime} UTC [ critical] Should be corrected immediately, but indicates failure in a primary system, an example is a loss of a backup ISP connection.
+{datetime} UTC [    alert] Should be corrected immediately, therefore notify staff who can fix the problem. An example would be the loss of a primary ISP connection.
+{datetime} UTC [emergency] A "panic" condition usually affecting multiple apps/servers/sites. At this level it would usually notify all tech staff on call.
+{datetime} UTC [     info] Cleaning up. Done

test/scenario/nocolor/run.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+set -o pipefail
+set -o errexit
+set -o nounset
+# set -o xtrace
+
+# Set magic variables for current FILE & DIR
+__dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+__file="${__dir}/$(basename "${BASH_SOURCE[0]}")"
+__base="$(basename ${__file} .sh)"
+__root="$(cd "$(dirname $(dirname $(dirname "${__dir}")))" && pwd)"
+
+echo "B3BP:STDIO_REPLACE_DATETIMES"
+
+env LOG_LEVEL=8 NO_COLOR=true bash "${__root}/main.sh" -f /tmp/x