From e54435c2e40b5aafb1520264e416d8d69f8181f1 Mon Sep 17 00:00:00 2001
From: Thomas von Dein <tom@vondein.org>
Date: Sat, 22 Oct 2022 10:21:39 +0200
Subject: [PATCH] added support for environment variables

---
 TODO.md       |  2 --
 cfg/config.go | 19 +++++++++++++++++++
 cmd/root.go   |  1 +
 tablizer.pod  | 17 +++++++++++++++++
 4 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/TODO.md b/TODO.md
index c78da84..896806a 100644
--- a/TODO.md
+++ b/TODO.md
@@ -2,8 +2,6 @@
 
 - rm printYamlData() log.Fatal(), maybe return error on all printers?
 
-- printShellData() checks Columns unnecessarily (compare to yaml or extended)
-
 ## Features to be implemented
 
 - add output mode csv
diff --git a/cfg/config.go b/cfg/config.go
index 7f1c829..a569016 100644
--- a/cfg/config.go
+++ b/cfg/config.go
@@ -19,6 +19,7 @@ package cfg
 import (
 	"fmt"
 	"github.com/gookit/color"
+	"os"
 )
 
 const DefaultSeparator string = `(\s\s+|\t)`
@@ -133,3 +134,21 @@ func (conf *Config) PrepareModeFlags(flag Modeflag) {
 		conf.OutputMode = Ascii
 	}
 }
+
+func (c *Config) CheckEnv() {
+	// check for environment vars, command line flags have precedence,
+	// NO_COLOR is being checked by the color module itself.
+	if !c.NoNumbering {
+		_, set := os.LookupEnv("T_NO_HEADER_NUMBERING")
+		if set {
+			c.NoNumbering = true
+		}
+	}
+
+	if len(c.Columns) == 0 {
+		cols := os.Getenv("T_COLUMNS")
+		if len(cols) > 1 {
+			c.Columns = cols
+		}
+	}
+}
diff --git a/cmd/root.go b/cmd/root.go
index 466c85d..d152ea3 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -70,6 +70,7 @@ func Execute() {
 			}
 
 			// prepare flags
+			conf.CheckEnv()
 			conf.PrepareModeFlags(modeflag)
 			conf.PrepareSortFlags(sortmode)
 
diff --git a/tablizer.pod b/tablizer.pod
index 68235b5..ee73053 100644
--- a/tablizer.pod
+++ b/tablizer.pod
@@ -209,6 +209,23 @@ more output modes available: B<orgtbl>  which prints an Emacs org-mode
 table and B<markdown> which prints a Markdown table and B<yaml>, which
 prints yaml encoding.
 
+=head2 ENVIRONMENT VARIABLES
+
+B<tablizer> supports  certain environment variables which  use can use
+to  influence   program  behavior.   Commandline  flags   have  always
+precedence over environment variables.
+
+=over
+
+=item <T_NO_HEADER_NUMBERING> - disable numbering of header fields, like B<-n>.
+
+=item <T_COLUMNS> - comma separated list of columns to output, like B<-c>
+
+=item <NO_COLORS> - disable colorization of matches, like B<-N>
+
+=back
+
+
 =head1 BUGS
 
 In order to report a bug, unexpected behavior, feature requests