added environment variable support

README.md

@@ -128,6 +128,13 @@ loglevel = verbose
 outdir = "test"
 ```
 
+## Environment Variables
+
+Kleingebaeck can also be configured using environment variables. Just prefix the config variables with `KLEINGEBAECK_` and put them to upper case. Eg:
+```shell
+% KLEINGEBAECK_OUTDIR=/backup kleingebaeck -v
+```
+
 ## Usage
 
 To setup the tool, you need to lookup your userid on

config.go

@@ -23,9 +23,11 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"strings"
 
 	"github.com/knadh/koanf/parsers/toml"
 	"github.com/knadh/koanf/providers/confmap"
+	"github.com/knadh/koanf/providers/env"
 	"github.com/knadh/koanf/providers/file"
 	"github.com/knadh/koanf/providers/posflag"
 	"github.com/knadh/koanf/v2"
@@ -162,7 +164,15 @@ func InitConfig(w io.Writer) (*Config, error) {
 		// else: we ignore the file if it doesn't exists
 	}
 
-	// command line overrides config file
+	// env overrides config file
+	if err := k.Load(env.Provider("KLEINGEBAECK_", ".", func(s string) string {
+		return strings.Replace(strings.ToLower(
+			strings.TrimPrefix(s, "KLEINGEBAECK_")), "_", ".", -1)
+	}), nil); err != nil {
+		return nil, errors.New("error loading environment: " + err.Error())
+	}
+
+	// command line overrides env
 	if err := k.Load(posflag.Provider(f, ".", k), nil); err != nil {
 		return nil, errors.New("error loading flags: " + err.Error())
 	}

go.mod

@@ -21,6 +21,7 @@ require (
 	github.com/andybalholm/cascadia v1.0.0 // indirect
 	github.com/fsnotify/fsnotify v1.6.0 // indirect
 	github.com/knadh/koanf/maps v0.1.1 // indirect
+	github.com/knadh/koanf/providers/env v0.1.0 // indirect
 	github.com/mitchellh/copystructure v1.2.0 // indirect
 	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/mitchellh/reflectwalk v1.0.2 // indirect

go.sum

@@ -17,6 +17,8 @@ github.com/knadh/koanf/parsers/toml v0.1.0 h1:S2hLqS4TgWZYj4/7mI5m1CQQcWurxUz6OD
 github.com/knadh/koanf/parsers/toml v0.1.0/go.mod h1:yUprhq6eo3GbyVXFFMdbfZSo928ksS+uo0FFqNMnO18=
 github.com/knadh/koanf/providers/confmap v0.1.0 h1:gOkxhHkemwG4LezxxN8DMOFopOPghxRVp7JbIvdvqzU=
 github.com/knadh/koanf/providers/confmap v0.1.0/go.mod h1:2uLhxQzJnyHKfxG927awZC7+fyHFdQkd697K4MdLnIU=
+github.com/knadh/koanf/providers/env v0.1.0 h1:LqKteXqfOWyx5Ab9VfGHmjY9BvRXi+clwyZozgVRiKg=
+github.com/knadh/koanf/providers/env v0.1.0/go.mod h1:RE8K9GbACJkeEnkl8L/Qcj8p4ZyPXZIQ191HJi44ZaQ=
 github.com/knadh/koanf/providers/file v0.1.0 h1:fs6U7nrV58d3CFAFh8VTde8TM262ObYf3ODrc//Lp+c=
 github.com/knadh/koanf/providers/file v0.1.0/go.mod h1:rjJ/nHQl64iYCtAW2QQnF0eSmDEX/YZ/eNFj5yR6BvA=
 github.com/knadh/koanf/providers/posflag v0.1.0 h1:mKJlLrKPcAP7Ootf4pBZWJ6J+4wHYujwipe7Ie3qW6U=

kleingebaeck.1

@@ -133,7 +133,7 @@
 .\" ========================================================================
 .\"
 .IX Title "KLEINGEBAECK 1"
-.TH KLEINGEBAECK 1 "2024-01-16" "1" "User Commands"
+.TH KLEINGEBAECK 1 "2024-01-17" "1" "User Commands"
 .\" For nroff, turn off justification.  Always turn off hyphenation; it makes
 .\" way too many mistakes in technical documents.
 .if n .ad l
@@ -219,6 +219,22 @@ directory. Then just execute \f(CW\*(C`kleingebaeck\*(C'\fR.
 .PP
 You can use the \fB\-v\fR option to  get verbose output or \fB\-d\fR to enable
 debugging.
+.SH "ENVIRONMENT VARIABLES"
+.IX Header "ENVIRONMENT VARIABLES"
+The following environment variables  are considered:
+.PP
+.Vb 7
+\&    KLEINGEBAECK_USER
+\&    KLEINGEBAECK_DEBUG
+\&    KLEINGEBAECK_VERBOSE
+\&    KLEINGEBAECK_OUTDIR
+\&    KLEINGEBAECK_LIMIT
+\&    KLEINGEBAECK_CONFIG
+\&    KLEINGEBAECK_IGNOREERRORS
+.Ve
+.PP
+Please  note,  that  they  take   precedence  over  config  file,  but
+commandline flags take precedence over env!
 .SH "BUGS"
 .IX Header "BUGS"
 In order to report a bug, unexpected behavior, feature requests

kleingebaeck.go

@@ -74,6 +74,20 @@ SETUP
     You can use the -v option to get verbose output or -d to enable
     debugging.
 
+ENVIRONMENT VARIABLES
+    The following environment variables are considered:
+
+        KLEINGEBAECK_USER
+        KLEINGEBAECK_DEBUG
+        KLEINGEBAECK_VERBOSE
+        KLEINGEBAECK_OUTDIR
+        KLEINGEBAECK_LIMIT
+        KLEINGEBAECK_CONFIG
+        KLEINGEBAECK_IGNOREERRORS
+
+    Please note, that they take precedence over config file, but commandline
+    flags take precedence over env!
+
 BUGS
     In order to report a bug, unexpected behavior, feature requests or to
     submit a patch, please open an issue on github:

kleingebaeck.pod

@@ -77,6 +77,23 @@ directory. Then just execute C<kleingebaeck>.
 You can use the B<-v> option to  get verbose output or B<-d> to enable
 debugging.
 
+=head1 ENVIRONMENT VARIABLES
+
+The following environment variables  are considered:
+
+    KLEINGEBAECK_USER
+    KLEINGEBAECK_DEBUG
+    KLEINGEBAECK_VERBOSE
+    KLEINGEBAECK_OUTDIR
+    KLEINGEBAECK_LIMIT
+    KLEINGEBAECK_CONFIG
+    KLEINGEBAECK_IGNOREERRORS
+
+Please  note,  that  they  take   precedence  over  config  file,  but
+commandline flags take precedence over env!
+
+
+
 =head1 BUGS
 
 In order to report a bug, unexpected behavior, feature requests