diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..b746a90
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,20 @@
+# Binaries for programs and plugins
+bin/*
+multini
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Custom binary test
+tests/out_ini/*
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..5150321
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,73 @@
+NAME=multini
+VERSION=0.1
+GOCMD=go
+LDFLAGS:="$(LDFLAGS) -X 'main.Version=$(VERSION)'"
+GOBUILD=$(GOCMD) build -ldflags=$(LDFLAGS)
+SRCMAIN=.
+BINDIR=bin
+BIN=$(BINDIR)/$(NAME)
+README=README
+LICENSE=LICENSE
+TEST=./run_test.sh
+PREFIX=/usr
+
+all: build
+
+prep: clean
+	mkdir $(BINDIR)
+	
+build: prep
+	$(GOBUILD) -o $(BIN) $(SRCMAIN)
+
+check-build:
+	test -e $(BIN)
+
+freebsd-386: prep
+	GOOS=freebsd GOARCH=386 $(GOBUILD) -o $(BIN)-freebsd-386 $(SRCMAIN)
+
+darwin-386: prep
+	GOOS=darwin GOARCH=386 $(GOBUILD) -o $(BIN)-darwin-386 $(SRCMAIN)
+
+linux-386: prep
+	GOOS=linux GOARCH=386 $(GOBUILD) -o $(BIN)-linux-386 $(SRCMAIN)
+
+windows-386: prep
+	GOOS=windows GOARCH=386 $(GOBUILD) -o $(BIN)-windows-386.exe $(SRCMAIN)
+	
+freebsd-amd64: prep
+	GOOS=freebsd GOARCH=amd64 $(GOBUILD) -o $(BIN)-freebsd-amd64 $(SRCMAIN)
+
+darwin-amd64: prep
+	GOOS=darwin GOARCH=amd64 $(GOBUILD) -o $(BIN)-darwin-amd64 $(SRCMAIN)
+
+linux-amd64: prep
+	GOOS=linux GOARCH=amd64 $(GOBUILD) -o $(BIN)-linux-amd64 $(SRCMAIN)
+
+windows-amd64: prep
+	GOOS=windows GOARCH=amd64 $(GOBUILD) -o $(BIN)-windows-amd64.exe $(SRCMAIN)
+
+compile: freebsd-386 darwin-386 linux-386 windows-386 freebsd-amd64 darwin-amd64 linux-amd64 windows-amd64
+	
+install: check-build
+	install -m 755 -d         $(PREFIX)/bin/
+	install -m 755 $(BIN)     $(PREFIX)/bin/
+	install -m 755 -d         $(PREFIX)/share/licenses/$(NAME)/
+	install -m 644 $(LICENSE) $(PREFIX)/share/licenses/$(NAME)/
+	install -m 755 -d         $(PREFIX)/share/doc/$(NAME)/
+	install -m 644 $(README)  $(PREFIX)/share/doc/$(NAME)/
+
+check-install:
+	test -e $(PREFIX)/bin/$(NAME) || \
+	test -d $(PREFIX)/share/licenses/$(NAME) || \
+	test -d $(PREFIX)/share/doc/$(NAME)
+
+uninstall: check-install
+	rm -f  $(PREFIX)/bin/$(NAME)
+	rm -rf $(PREFIX)/share/licenses/$(NAME)
+	rm -rf $(PREFIX)/share/doc/$(NAME)
+
+clean:
+	rm -rf $(BINDIR)
+	
+test: check-build
+	$(TEST) $(BIN)
diff --git a/README b/README
new file mode 100644
index 0000000..7f46841
--- /dev/null
+++ b/README
@@ -0,0 +1,22 @@
+A utility for manipulating ini files with duplicate keys
+
+Usage: multini [OPTION]... [ACTION] config_file [section] [param] [value]
+Actions:
+  -g, --get          get values for a given combination of parameters.
+  -s, --set          set values for a given combination of parameters.
+  -a, --add          add values for a given combination of parameters.
+  -d, --del          delete the given combination of parameters.
+  -c, --chk          display parsing errors for the specified file.
+
+Options:
+  -e, --existing     For --set and --del, fail if item is missing.
+  -i, --inplace      Lock and write files in place.
+                     This is not atomic but has less restrictions
+                     than the default replacement method.
+  -o, --output FILE  Write output to FILE instead. '-' means stdout
+  -u, --unix         Use LF as end of line
+  -w, --windows      Use CRLF as end of line
+  -h, --help         Write this help to stdout
+      --version      Write version to stdout
+
+2020 (c) GenZmeY
diff --git a/actions.go b/actions.go
new file mode 100644
index 0000000..63775c1
--- /dev/null
+++ b/actions.go
@@ -0,0 +1,68 @@
+package main
+
+import (
+	"multini/output"
+	"multini/types"
+)
+
+func chk() int {
+	var ok bool
+	var err error
+	ok, err = iniCheck(ArgFile)
+	if err != nil {
+		output.Errorln(err)
+		return EXIT_FILE_READ_ERR
+	}
+	if ok {
+		return EXIT_SUCCESS
+	} else {
+		return EXIT_BAD_SYNTAX_ERR
+	}
+}
+
+func add(ini *types.Ini) error {
+	if ArgKeyIsSet {
+		return ini.AddKey(ArgSection, ArgKey, ArgValue)
+	} else {
+		ini.AddSection(ArgSection)
+		return nil
+	}
+}
+
+func set(ini *types.Ini) error {
+	if ArgKeyIsSet {
+		return ini.SetKey(ArgSection, ArgKey, ArgValue)
+	} else {
+		ini.SetSection(ArgSection)
+		return nil
+	}
+}
+
+func get(ini *types.Ini) error {
+	var err error = nil
+	var res string
+	if ArgValueIsSet {
+		return ini.GetKeyVal(ArgSection, ArgKey, ArgValue)
+	} else if ArgKeyIsSet {
+		res, err = ini.GetKey(ArgSection, ArgKey)
+	} else if ArgSectionIsSet {
+		res, err = ini.GetSection(ArgSection)
+	} else {
+		res = ini.Get()
+	}
+
+	if err == nil {
+		output.Println(res)
+	}
+	return err
+}
+
+func del(ini *types.Ini) error {
+	if ArgValueIsSet {
+		return ini.DelKeyVal(ArgSection, ArgKey, ArgValue)
+	} else if ArgKeyIsSet {
+		return ini.DelKey(ArgSection, ArgKey)
+	} else {
+		return ini.DelSection(ArgSection)
+	}
+}
diff --git a/args.go b/args.go
new file mode 100644
index 0000000..2b07e33
--- /dev/null
+++ b/args.go
@@ -0,0 +1,177 @@
+package main
+
+import (
+	"errors"
+	"os"
+
+	"multini/output"
+	"multini/types"
+
+	"github.com/juju/gnuflag"
+)
+
+var (
+	ArgInplace  bool
+	ArgGet      bool
+	ArgSet      bool
+	ArgAdd      bool
+	ArgDel      bool
+	ArgChk      bool
+	ArgVerbose  bool
+	ArgVersion  bool
+	ArgWindows  bool
+	ArgUnix     bool
+	ArgHelp     bool
+	ArgExisting bool
+	ArgOutput   string
+
+	ArgFile         string
+	ArgFileIsSet    bool = false
+	ArgSection      string
+	ArgSectionIsSet bool = false
+	ArgKey          string
+	ArgKeyIsSet     bool = false
+	ArgValue        string
+	ArgValueIsSet   bool = false
+)
+
+func printHelp() {
+	output.Println("A utility for manipulating ini files with duplicate keys")
+	output.Println("")
+	output.Println("Usage: multini [OPTION]... [ACTION] config_file [section] [param] [value]")
+	output.Println("Actions:")
+	output.Println("  -g, --get          get values for a given combination of parameters.")
+	output.Println("  -s, --set          set values for a given combination of parameters.")
+	output.Println("  -a, --add          add values for a given combination of parameters.")
+	output.Println("  -d, --del          delete the given combination of parameters.")
+	output.Println("  -c, --chk          display parsing errors for the specified file.")
+	output.Println("")
+	output.Println("Options:")
+	output.Println("  -e, --existing     For --set and --del, fail if item is missing.")
+	output.Println("  -i, --inplace      Lock and write files in place.")
+	output.Println("                     This is not atomic but has less restrictions")
+	output.Println("                     than the default replacement method.")
+	output.Println("  -o, --output FILE  Write output to FILE instead. '-' means stdout")
+	//	output.Println("  -v, --verbose      Indicate on stderr if changes were made")
+	output.Println("  -u, --unix         Use LF as end of line")
+	output.Println("  -w, --windows      Use CRLF as end of line")
+	output.Println("  -h, --help         Write this help to stdout")
+	output.Println("      --version      Write version to stdout")
+}
+
+func printVersion() {
+	output.Println("multini ", Version)
+}
+
+func init() {
+	gnuflag.BoolVar(&ArgGet, "get", false, "")
+	gnuflag.BoolVar(&ArgGet, "g", false, "")
+	gnuflag.BoolVar(&ArgAdd, "add", false, "")
+	gnuflag.BoolVar(&ArgAdd, "a", false, "")
+	gnuflag.BoolVar(&ArgSet, "set", false, "")
+	gnuflag.BoolVar(&ArgSet, "s", false, "")
+	gnuflag.BoolVar(&ArgDel, "del", false, "")
+	gnuflag.BoolVar(&ArgDel, "d", false, "")
+	gnuflag.BoolVar(&ArgChk, "chk", false, "")
+	gnuflag.BoolVar(&ArgChk, "c", false, "")
+	gnuflag.BoolVar(&ArgDel, "inplace", false, "")
+	gnuflag.BoolVar(&ArgDel, "i", false, "")
+	gnuflag.BoolVar(&ArgUnix, "unix", false, "")
+	gnuflag.BoolVar(&ArgUnix, "u", false, "")
+	gnuflag.BoolVar(&ArgWindows, "windows", false, "")
+	gnuflag.BoolVar(&ArgWindows, "w", false, "")
+	gnuflag.BoolVar(&ArgExisting, "existing", false, "")
+	gnuflag.BoolVar(&ArgExisting, "e", false, "")
+	gnuflag.BoolVar(&ArgVerbose, "verbose", false, "")
+	gnuflag.BoolVar(&ArgVerbose, "v", false, "")
+	gnuflag.StringVar(&ArgOutput, "output", "", "")
+	gnuflag.StringVar(&ArgOutput, "o", "", "")
+	gnuflag.BoolVar(&ArgVersion, "version", false, "")
+	gnuflag.BoolVar(&ArgHelp, "help", false, "")
+	gnuflag.BoolVar(&ArgHelp, "h", false, "")
+}
+
+func parseArgs() error {
+	gnuflag.Parse(true)
+
+	// info
+	switch {
+	case ArgHelp:
+		printHelp()
+		os.Exit(EXIT_SUCCESS)
+	case ArgVersion:
+		printVersion()
+		os.Exit(EXIT_SUCCESS)
+	}
+
+	// File EOF
+	switch {
+	case ArgWindows:
+		types.SetEndOfLineWindows()
+	case ArgUnix:
+		types.SetEndOfLineUnix()
+	default:
+		types.SetEndOfLineNative()
+	}
+
+	// Output settings
+	output.SetEndOfLineNative()
+	output.SetVerbose(ArgVerbose)
+
+	// Positional Args
+	for i := 0; i < 4 && i < gnuflag.NArg(); i++ {
+		switch i {
+		case 0:
+			ArgFile = gnuflag.Arg(0)
+			ArgFileIsSet = true
+		case 1:
+			ArgSection = gnuflag.Arg(1)
+			ArgSectionIsSet = true
+		case 2:
+			ArgKey = gnuflag.Arg(2)
+			ArgKeyIsSet = true
+		case 3:
+			ArgValue = gnuflag.Arg(3)
+			ArgValueIsSet = true
+		}
+	}
+
+	if !ArgFileIsSet {
+		return errors.New("Config_file not specified")
+	}
+
+	// Mode
+	actionCounter := 0
+	if ArgChk {
+		actionCounter++
+	}
+	if ArgDel {
+		actionCounter++
+		if !ArgSectionIsSet {
+			return errors.New("Section not specified")
+		}
+	}
+	if ArgGet {
+		actionCounter++
+	}
+	if ArgSet {
+		actionCounter++
+		if !ArgSectionIsSet {
+			return errors.New("Section not specified")
+		}
+	}
+	if ArgAdd {
+		actionCounter++
+		if !ArgSectionIsSet {
+			return errors.New("Section not specified")
+		}
+	}
+	switch actionCounter {
+	case 0:
+		return errors.New("Action not set")
+	case 1:
+		return nil
+	default:
+		return errors.New("Only one action can be used at the same time")
+	}
+}
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..40e3390
--- /dev/null
+++ b/main.go
@@ -0,0 +1,80 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"multini/output"
+	"multini/types"
+)
+
+const (
+	EXIT_SUCCESS           int = 0
+	EXIT_ARG_ERR           int = 1
+	EXIT_FILE_READ_ERR     int = 2
+	EXIT_BAD_SYNTAX_ERR    int = 3
+	EXIT_ELEMENT_NOT_FOUND int = 4
+	EXIT_FILE_WRITE_ERR    int = 5
+	EXIT_ACTION_ERR        int = 6
+)
+
+var (
+	Version string = "development"
+)
+
+func main() {
+	var err error
+	var ini types.Ini
+
+	if err = parseArgs(); err != nil {
+		output.Errorln(err)
+		os.Exit(EXIT_ARG_ERR)
+	}
+
+	if ArgChk {
+		os.Exit(chk())
+	}
+
+	ini, err = iniRead(ArgFile)
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(EXIT_FILE_READ_ERR)
+	}
+
+	switch {
+	case ArgGet:
+		err = get(&ini)
+	case ArgAdd:
+		err = add(&ini)
+	case ArgDel:
+		err = del(&ini)
+	case ArgSet:
+		err = set(&ini)
+	}
+
+	if err != nil {
+		output.Errorln(err)
+		os.Exit(EXIT_ACTION_ERR)
+	}
+
+	if ArgOutput == "-" {
+		output.Println(ini.Full())
+		os.Exit(EXIT_SUCCESS)
+	} else if ArgOutput != "" {
+		ArgFile = ArgOutput
+	}
+
+	if ArgAdd || ArgSet || ArgDel {
+		if ArgInplace || ArgOutput != "" {
+			err = iniWriteInplace(ArgFile, &ini)
+		} else {
+			err = iniWrite(ArgFile, &ini)
+		}
+		if err != nil {
+			output.Errorln(err)
+			os.Exit(EXIT_FILE_WRITE_ERR)
+		}
+	}
+
+	os.Exit(EXIT_SUCCESS)
+}
diff --git a/output/output.go b/output/output.go
new file mode 100644
index 0000000..b61f4a2
--- /dev/null
+++ b/output/output.go
@@ -0,0 +1,82 @@
+package output
+
+import (
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"runtime"
+)
+
+var (
+	endOfLine string      = "\n"
+	devNull   *log.Logger = log.New(ioutil.Discard, "", 0)
+	stdout    *log.Logger = log.New(os.Stdout, "", 0)
+	stderr    *log.Logger = log.New(os.Stderr, "", 0)
+	verbose   *log.Logger = devNull
+)
+
+func SetVerbose(enabled bool) {
+	if enabled {
+		verbose = stderr
+	} else {
+		verbose = devNull
+	}
+}
+
+func SetEndOfLineNative() {
+	switch os := runtime.GOOS; os {
+	case "windows":
+		setEndOfLineWindows()
+	default:
+		setEndOfLineUnix()
+	}
+}
+
+func EOL() string {
+	return endOfLine
+}
+
+func setEndOfLineUnix() {
+	endOfLine = "\n"
+}
+
+func setEndOfLineWindows() {
+	endOfLine = "\r\n"
+}
+
+func Print(v ...interface{}) {
+	stdout.Print(v...)
+}
+
+func Printf(format string, v ...interface{}) {
+	stdout.Printf(format, v...)
+}
+
+func Println(v ...interface{}) {
+	stdout.Print(fmt.Sprint(v...) + endOfLine)
+}
+
+func Error(v ...interface{}) {
+	stderr.Print(v...)
+}
+
+func Errorf(format string, v ...interface{}) {
+	stderr.Printf(format, v...)
+}
+
+func Errorln(v ...interface{}) {
+	stderr.Print(fmt.Sprint(v...) + endOfLine)
+}
+
+func Verbose(v ...interface{}) {
+	verbose.Print(v...)
+}
+
+func Verbosef(format string, v ...interface{}) {
+	verbose.Printf(format, v...)
+}
+
+func Verboseln(v ...interface{}) {
+	verbose.Print(fmt.Sprint(v...) + endOfLine)
+}
diff --git a/reader.go b/reader.go
new file mode 100644
index 0000000..7325b04
--- /dev/null
+++ b/reader.go
@@ -0,0 +1,182 @@
+package main
+
+import (
+	"bufio"
+	"errors"
+	"os"
+	"regexp"
+	"strings"
+
+	"multini/output"
+	"multini/types"
+)
+
+var (
+	// Ng - Named Group
+	NgPrefix        string = `prefix`
+	NgPostifx       string = `postfix`
+	NgSection       string = `section`
+	NgKey           string = `key`
+	NgKeyPostfix    string = `key_postfix`
+	NgValue         string = `value`
+	NgValuePrefix   string = `value_prefix`
+	NgValuePostfix  string = `value_postfix`
+	NgComment       string = `comment`
+	NgCommentPrefix string = `comment_prefix`
+
+	RxBodyPrefix    string         = `(?P<` + NgPrefix + `>\s+)?`
+	RxSectionName   string         = `\[(?P<` + NgSection + `>.+)\]`
+	RxKey           string         = `(?P<` + NgKey + `>(?:[^;#=]+[^\s=;#]|[^;#=]))?`
+	RxKeyPostfix    string         = `(?P<` + NgKeyPostfix + `>\s+)?`
+	RxValuePrefix   string         = `(?P<` + NgValuePrefix + `>\s+)?`
+	RxValue         string         = `(?P<` + NgValue + `>(?:[^;#]+[^\s;#]|[^;#]))?`
+	RxValuePostfix  string         = `(?P<` + NgValuePostfix + `>\s+)?`
+	RxKeyVal        string         = RxKey + RxKeyPostfix + `=` + RxValuePrefix + RxValue + RxValuePostfix
+	RxBody          string         = `(?:` + RxSectionName + `|` + RxKeyVal + `)?`
+	RxBodyPostfix   string         = `(?P<` + NgPostifx + `>\s+)?`
+	RxCommentPrefix string         = `(?P<` + NgCommentPrefix + `>[#;]\s*)`
+	RxCommentText   string         = `(?P<` + NgComment + `>.+)?`
+	RxComment       string         = `(?:` + RxCommentPrefix + RxCommentText + `)?`
+	Rx              string         = RxBodyPrefix + RxBody + RxBodyPostfix + RxComment
+	RxCompiled      *regexp.Regexp = regexp.MustCompile(Rx)
+)
+
+func rxParse(rx *regexp.Regexp, str string) map[string]string {
+	match := rx.FindStringSubmatch(str)
+	result := make(map[string]string)
+	for i, name := range rx.SubexpNames() {
+		if i != 0 && name != "" && i <= len(match) {
+			result[name] = match[i]
+		}
+	}
+	return result
+}
+
+func debugMap(el map[string]string) string {
+	var dbgMap strings.Builder
+	for key, val := range el {
+		dbgMap.WriteString("  " + key + ": \"" + val + "\"" + output.EOL())
+	}
+	return dbgMap.String()
+}
+
+func appendLine(ini *types.Ini, line string) error {
+	elements := rxParse(RxCompiled, line)
+	switch {
+	case elements[NgSection] != "":
+		var newSection types.Section
+		newSection.Name = elements[NgSection]
+		newSection.Prefix = elements[NgPrefix]
+		newSection.Postfix = elements[NgPostifx]
+		newSection.Comment.Prefix = elements[NgCommentPrefix]
+		newSection.Comment.Value = elements[NgComment]
+		if newSection.Line() == line {
+			ini.Sections = append(ini.Sections, &newSection)
+			return nil
+		} else {
+			output.Verboseln("Got:", newSection.Line())
+			var newTrash types.Trash = types.Trash{Value: line}
+			ini.Sections[len(ini.Sections)-1].(*types.Section).Lines = append(ini.Sections[len(ini.Sections)-1].(*types.Section).Lines, &newTrash)
+		}
+	case elements[NgKey] != "":
+		var newKeyValue types.KeyValue
+		newKeyValue.Key = elements[NgKey]
+		newKeyValue.PostfixKey = elements[NgKeyPostfix]
+		newKeyValue.PrefixKey = elements[NgPrefix]
+		newKeyValue.Value = elements[NgValue]
+		newKeyValue.PrefixValue = elements[NgValuePrefix]
+		newKeyValue.PostfixValue = elements[NgValuePostfix]
+		newKeyValue.Comment.Value = elements[NgComment]
+		newKeyValue.Comment.Prefix = elements[NgCommentPrefix]
+		if newKeyValue.Line() == line {
+			ini.Sections[len(ini.Sections)-1].(*types.Section).Lines = append(ini.Sections[len(ini.Sections)-1].(*types.Section).Lines, &newKeyValue)
+			return nil
+		} else {
+			output.Verboseln("Got:", newKeyValue.Line())
+			var newTrash types.Trash = types.Trash{Value: line}
+			ini.Sections[len(ini.Sections)-1].(*types.Section).Lines = append(ini.Sections[len(ini.Sections)-1].(*types.Section).Lines, &newTrash)
+		}
+	case elements[NgComment] != "":
+		var newComment types.Comment
+		newComment.Prefix = elements[NgPrefix] + elements[NgCommentPrefix]
+		newComment.Value = elements[NgComment]
+		if newComment.Line() == line {
+			ini.Sections[len(ini.Sections)-1].(*types.Section).Lines = append(ini.Sections[len(ini.Sections)-1].(*types.Section).Lines, &newComment)
+			return nil
+		} else {
+			output.Verboseln("Got:", newComment.Line())
+			var newTrash types.Trash = types.Trash{Value: line}
+			ini.Sections[len(ini.Sections)-1].(*types.Section).Lines = append(ini.Sections[len(ini.Sections)-1].(*types.Section).Lines, &newTrash)
+		}
+	case elements[NgPrefix] != "" || line == "":
+		var newEmptyLine types.EmptyLine
+		newEmptyLine.Prefix = elements[NgPrefix]
+		if newEmptyLine.Line() == line {
+			ini.Sections[len(ini.Sections)-1].(*types.Section).Lines = append(ini.Sections[len(ini.Sections)-1].(*types.Section).Lines, &newEmptyLine)
+			return nil
+		} else {
+			output.Verboseln("Got:", newEmptyLine.Line())
+			var newTrash types.Trash = types.Trash{Value: line}
+			ini.Sections[len(ini.Sections)-1].(*types.Section).Lines = append(ini.Sections[len(ini.Sections)-1].(*types.Section).Lines, &newTrash)
+		}
+	default:
+		var newTrash types.Trash = types.Trash{Value: line}
+		ini.Sections[len(ini.Sections)-1].(*types.Section).Lines = append(ini.Sections[len(ini.Sections)-1].(*types.Section).Lines, &newTrash)
+	}
+	return errors.New(debugMap(elements))
+}
+
+func iniRead(filename string) (types.Ini, error) {
+	var (
+		err     error
+		iniFile *os.File
+		ini     types.Ini
+	)
+	iniFile, err = os.Open(filename)
+
+	if err != nil {
+		return ini, err
+	}
+
+	fileScanner := bufio.NewScanner(iniFile)
+	fileScanner.Split(bufio.ScanLines)
+	ini.Init()
+
+	for i := 1; fileScanner.Scan(); i++ {
+		appendLine(&ini, fileScanner.Text())
+	}
+
+	iniFile.Close()
+	return ini, nil
+}
+
+func iniCheck(filename string) (bool, error) {
+	var (
+		err     error
+		iniFile *os.File
+		ini     types.Ini
+		ok      bool = true
+	)
+	iniFile, err = os.Open(filename)
+
+	if err != nil {
+		return ok, err
+	}
+
+	fileScanner := bufio.NewScanner(iniFile)
+	fileScanner.Split(bufio.ScanLines)
+	ini.Init()
+
+	for i := 1; fileScanner.Scan(); i++ {
+		line := fileScanner.Text()
+		err = appendLine(&ini, line)
+		if err != nil {
+			output.Errorln(i, ":", line)
+			output.Verboseln(err)
+			ok = false
+		}
+	}
+
+	iniFile.Close()
+	return ok, nil
+}
diff --git a/run_test.sh b/run_test.sh
new file mode 100755
index 0000000..096030c
--- /dev/null
+++ b/run_test.sh
@@ -0,0 +1,29 @@
+#!/bin/bash
+
+DEF='\e[0m'; BLD='\e[1m'; RED='\e[31m'; GRN='\e[32m'; WHT='\e[97m'
+ScriptFullname=$(readlink -e "$0")
+ScriptName=$(echo "$ScriptFullname" | awk -F '/' '{print $NF;}')
+ScriptDir=$(dirname "$ScriptFullname")
+TestDir="$ScriptDir/tests"
+Multini=$(readlink -e "$1")
+
+if [[ -z "$Multini" ]]; then
+	Multini="$ScriptDir/multini"
+fi
+
+RetCode=0
+pushd "$TestDir" > /dev/null
+while read Test
+do
+	echo -ne "${BLD}${WHT}[----]${DEF} $Test"
+	Errors=$("$TestDir/$Test" "$Multini")
+	if [[ $? -ne 0 ]]; then
+		echo -e "\r${BLD}${WHT}[${RED}FAIL${WHT}]${DEF} $Test"
+		RetCode=1
+		echo "$Errors"
+	else
+		echo -e "\r${BLD}${WHT}[${GRN} OK ${WHT}]${DEF} $Test"
+	fi
+done < <(find "$TestDir" -type f -name 'test_*.sh' -printf "%f\n")
+popd > /dev/null
+exit "$RetCode"
diff --git a/tests/common.sh b/tests/common.sh
new file mode 100755
index 0000000..51d8d77
--- /dev/null
+++ b/tests/common.sh
@@ -0,0 +1,27 @@
+#!/bin/bash
+
+ScriptFullname=$(readlink -e "$0")
+ScriptName=$(echo "$ScriptFullname" | awk -F '/' '{print $NF;}')
+ScriptDir=$(dirname "$ScriptFullname")
+Multini="$1"
+InDir="$ScriptDir/in_ini"
+InIni="$InDir/$ScriptName.ini"
+OutDir="$ScriptDir/out_ini"
+OutIni="$OutDir/$ScriptName.ini"
+ExpectedIni="$ScriptDir/expected_ini/$ScriptName.ini"
+
+if [[ ! -d "$OutDir" ]]; then
+	mkdir -p "$OutDir"
+fi
+
+rm -f "$OutIni"
+
+function compare ()
+{
+	if ! cmp -s "$OutIni" "$ExpectedIni" ; then
+		diff "$OutIni" "$ExpectedIni"
+		return 1
+	fi
+	rm -f "$OutIni"
+	return 0
+}
diff --git a/tests/expected_ini/test_add_keyval.sh.ini b/tests/expected_ini/test_add_keyval.sh.ini
new file mode 100644
index 0000000..0394419
--- /dev/null
+++ b/tests/expected_ini/test_add_keyval.sh.ini
@@ -0,0 +1,20 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+	Key3 = 3
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/expected_ini/test_add_keyval_existing.sh.ini b/tests/expected_ini/test_add_keyval_existing.sh.ini
new file mode 100644
index 0000000..1097509
--- /dev/null
+++ b/tests/expected_ini/test_add_keyval_existing.sh.ini
@@ -0,0 +1,20 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	Key = 4
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/expected_ini/test_add_section.sh.ini b/tests/expected_ini/test_add_section.sh.ini
new file mode 100644
index 0000000..a528b1a
--- /dev/null
+++ b/tests/expected_ini/test_add_section.sh.ini
@@ -0,0 +1,20 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
+[NewSection]
diff --git a/tests/expected_ini/test_del_key.sh.ini b/tests/expected_ini/test_del_key.sh.ini
new file mode 100644
index 0000000..893fe31
--- /dev/null
+++ b/tests/expected_ini/test_del_key.sh.ini
@@ -0,0 +1,18 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/expected_ini/test_del_key_multiple.sh.ini b/tests/expected_ini/test_del_key_multiple.sh.ini
new file mode 100644
index 0000000..49b2155
--- /dev/null
+++ b/tests/expected_ini/test_del_key_multiple.sh.ini
@@ -0,0 +1,16 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/expected_ini/test_del_keyval.sh.ini b/tests/expected_ini/test_del_keyval.sh.ini
new file mode 100644
index 0000000..6d56286
--- /dev/null
+++ b/tests/expected_ini/test_del_keyval.sh.ini
@@ -0,0 +1,18 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/expected_ini/test_del_section.sh.ini b/tests/expected_ini/test_del_section.sh.ini
new file mode 100644
index 0000000..6e8709a
--- /dev/null
+++ b/tests/expected_ini/test_del_section.sh.ini
@@ -0,0 +1,17 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+[SectionWithoutNewLineBefore]
diff --git a/tests/expected_ini/test_get_key.sh.ini b/tests/expected_ini/test_get_key.sh.ini
new file mode 100644
index 0000000..20bb86d
--- /dev/null
+++ b/tests/expected_ini/test_get_key.sh.ini
@@ -0,0 +1 @@
+Some Value2 And Tabs!
diff --git a/tests/expected_ini/test_get_key_multiple.sh.ini b/tests/expected_ini/test_get_key_multiple.sh.ini
new file mode 100644
index 0000000..01e79c3
--- /dev/null
+++ b/tests/expected_ini/test_get_key_multiple.sh.ini
@@ -0,0 +1,3 @@
+1
+2
+3
diff --git a/tests/expected_ini/test_get_keyval.sh.ini b/tests/expected_ini/test_get_keyval.sh.ini
new file mode 100644
index 0000000..e69de29
diff --git a/tests/expected_ini/test_get_section.sh.ini b/tests/expected_ini/test_get_section.sh.ini
new file mode 100644
index 0000000..58aabb7
--- /dev/null
+++ b/tests/expected_ini/test_get_section.sh.ini
@@ -0,0 +1,7 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
diff --git a/tests/expected_ini/test_get_section_list.sh.ini b/tests/expected_ini/test_get_section_list.sh.ini
new file mode 100644
index 0000000..eed0f4c
--- /dev/null
+++ b/tests/expected_ini/test_get_section_list.sh.ini
@@ -0,0 +1,5 @@
+
+SimpleSection
+MultipleKeySection
+SectionWithIndent
+SectionWithoutNewLineBefore
diff --git a/tests/expected_ini/test_set_keyval.sh.ini b/tests/expected_ini/test_set_keyval.sh.ini
new file mode 100644
index 0000000..dac4738
--- /dev/null
+++ b/tests/expected_ini/test_set_keyval.sh.ini
@@ -0,0 +1,17 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = onlyone
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/in_ini/test_add_keyval.sh.ini b/tests/in_ini/test_add_keyval.sh.ini
new file mode 100644
index 0000000..e96cbb7
--- /dev/null
+++ b/tests/in_ini/test_add_keyval.sh.ini
@@ -0,0 +1,19 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/in_ini/test_add_keyval_existing.sh.ini b/tests/in_ini/test_add_keyval_existing.sh.ini
new file mode 100644
index 0000000..e96cbb7
--- /dev/null
+++ b/tests/in_ini/test_add_keyval_existing.sh.ini
@@ -0,0 +1,19 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/in_ini/test_add_section.sh.ini b/tests/in_ini/test_add_section.sh.ini
new file mode 100644
index 0000000..e96cbb7
--- /dev/null
+++ b/tests/in_ini/test_add_section.sh.ini
@@ -0,0 +1,19 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/in_ini/test_del_key.sh.ini b/tests/in_ini/test_del_key.sh.ini
new file mode 100644
index 0000000..e96cbb7
--- /dev/null
+++ b/tests/in_ini/test_del_key.sh.ini
@@ -0,0 +1,19 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/in_ini/test_del_key_multiple.sh.ini b/tests/in_ini/test_del_key_multiple.sh.ini
new file mode 100644
index 0000000..e96cbb7
--- /dev/null
+++ b/tests/in_ini/test_del_key_multiple.sh.ini
@@ -0,0 +1,19 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/in_ini/test_del_keyval.sh.ini b/tests/in_ini/test_del_keyval.sh.ini
new file mode 100644
index 0000000..e96cbb7
--- /dev/null
+++ b/tests/in_ini/test_del_keyval.sh.ini
@@ -0,0 +1,19 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/in_ini/test_del_section.sh.ini b/tests/in_ini/test_del_section.sh.ini
new file mode 100644
index 0000000..e96cbb7
--- /dev/null
+++ b/tests/in_ini/test_del_section.sh.ini
@@ -0,0 +1,19 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/in_ini/test_get_key.sh.ini b/tests/in_ini/test_get_key.sh.ini
new file mode 100644
index 0000000..e96cbb7
--- /dev/null
+++ b/tests/in_ini/test_get_key.sh.ini
@@ -0,0 +1,19 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/in_ini/test_get_key_multiple.sh.ini b/tests/in_ini/test_get_key_multiple.sh.ini
new file mode 100644
index 0000000..e96cbb7
--- /dev/null
+++ b/tests/in_ini/test_get_key_multiple.sh.ini
@@ -0,0 +1,19 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/in_ini/test_get_keyval.sh.ini b/tests/in_ini/test_get_keyval.sh.ini
new file mode 100644
index 0000000..e96cbb7
--- /dev/null
+++ b/tests/in_ini/test_get_keyval.sh.ini
@@ -0,0 +1,19 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/in_ini/test_get_section.sh.ini b/tests/in_ini/test_get_section.sh.ini
new file mode 100644
index 0000000..e96cbb7
--- /dev/null
+++ b/tests/in_ini/test_get_section.sh.ini
@@ -0,0 +1,19 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/in_ini/test_get_section_list.sh.ini b/tests/in_ini/test_get_section_list.sh.ini
new file mode 100644
index 0000000..e96cbb7
--- /dev/null
+++ b/tests/in_ini/test_get_section_list.sh.ini
@@ -0,0 +1,19 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/in_ini/test_set_keyval.sh.ini b/tests/in_ini/test_set_keyval.sh.ini
new file mode 100644
index 0000000..e96cbb7
--- /dev/null
+++ b/tests/in_ini/test_set_keyval.sh.ini
@@ -0,0 +1,19 @@
+# comment
+; comment again
+
+DefKey1 = Some Value1
+DefKey2		=	Some Value2 And Tabs! # With Comment
+DefKey3=NoSpaces!
+
+[SimpleSection] # Comment For Section
+	Key1 = 1
+	Key2 = 2
+
+[MultipleKeySection]
+	Key = 1
+	Key = 2
+	Key = 3
+	
+	[SectionWithIndent]
+	Key=Value
+[SectionWithoutNewLineBefore]
diff --git a/tests/test_add_keyval.sh b/tests/test_add_keyval.sh
new file mode 100755
index 0000000..96debc7
--- /dev/null
+++ b/tests/test_add_keyval.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+source "common.sh"
+
+$Multini -o "$OutIni" --add "$InIni" SimpleSection Key3 3
+
+compare
diff --git a/tests/test_add_keyval_existing.sh b/tests/test_add_keyval_existing.sh
new file mode 100755
index 0000000..7049c04
--- /dev/null
+++ b/tests/test_add_keyval_existing.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+source "common.sh"
+
+$Multini -o "$OutIni" --add "$InIni" MultipleKeySection Key 4
+
+compare
diff --git a/tests/test_add_section.sh b/tests/test_add_section.sh
new file mode 100755
index 0000000..59df2da
--- /dev/null
+++ b/tests/test_add_section.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+source "common.sh"
+
+$Multini -o "$OutIni" --add "$InIni" NewSection
+
+compare
diff --git a/tests/test_del_key.sh b/tests/test_del_key.sh
new file mode 100755
index 0000000..9570332
--- /dev/null
+++ b/tests/test_del_key.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+source "common.sh"
+
+$Multini -o "$OutIni" --del "$InIni" SimpleSection Key1
+
+compare
diff --git a/tests/test_del_key_multiple.sh b/tests/test_del_key_multiple.sh
new file mode 100755
index 0000000..12d405e
--- /dev/null
+++ b/tests/test_del_key_multiple.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+source "common.sh"
+
+$Multini -o "$OutIni" --del "$InIni" MultipleKeySection Key
+
+compare
diff --git a/tests/test_del_keyval.sh b/tests/test_del_keyval.sh
new file mode 100755
index 0000000..7126cfa
--- /dev/null
+++ b/tests/test_del_keyval.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+source "common.sh"
+
+$Multini -o "$OutIni" --del "$InIni" MultipleKeySection Key 2
+
+compare
diff --git a/tests/test_del_section.sh b/tests/test_del_section.sh
new file mode 100755
index 0000000..b641a0d
--- /dev/null
+++ b/tests/test_del_section.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+source "common.sh"
+
+$Multini -o "$OutIni" --del "$InIni" SectionWithIndent
+
+compare
diff --git a/tests/test_get_key.sh b/tests/test_get_key.sh
new file mode 100755
index 0000000..2d7caa0
--- /dev/null
+++ b/tests/test_get_key.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+source "common.sh"
+
+$Multini --get "$InIni" '' DefKey2 > "$OutIni"
+
+compare
diff --git a/tests/test_get_key_multiple.sh b/tests/test_get_key_multiple.sh
new file mode 100755
index 0000000..1d5dda0
--- /dev/null
+++ b/tests/test_get_key_multiple.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+source "common.sh"
+
+$Multini --get "$InIni" MultipleKeySection Key > "$OutIni"
+
+compare
diff --git a/tests/test_get_keyval.sh b/tests/test_get_keyval.sh
new file mode 100755
index 0000000..cdba71a
--- /dev/null
+++ b/tests/test_get_keyval.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+source "common.sh"
+
+$Multini --get "$InIni" MultipleKeySection Key 3 > "$OutIni"
+
+compare
diff --git a/tests/test_get_section.sh b/tests/test_get_section.sh
new file mode 100755
index 0000000..cb93f93
--- /dev/null
+++ b/tests/test_get_section.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+source "common.sh"
+
+$Multini --get "$InIni" '' > "$OutIni"
+
+compare
diff --git a/tests/test_get_section_list.sh b/tests/test_get_section_list.sh
new file mode 100755
index 0000000..133445b
--- /dev/null
+++ b/tests/test_get_section_list.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+source "common.sh"
+
+$Multini --get "$InIni" > "$OutIni"
+
+compare
diff --git a/tests/test_set_keyval.sh b/tests/test_set_keyval.sh
new file mode 100755
index 0000000..03b7a1d
--- /dev/null
+++ b/tests/test_set_keyval.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+source "common.sh"
+
+$Multini -o "$OutIni" --set "$InIni" MultipleKeySection Key onlyone
+
+compare
diff --git a/types/comment.go b/types/comment.go
new file mode 100644
index 0000000..5f8919f
--- /dev/null
+++ b/types/comment.go
@@ -0,0 +1,26 @@
+package types
+
+type Comment struct {
+	Prefix string
+	Value  string
+}
+
+func (obj *Comment) Full() string {
+	return obj.Prefix + obj.Value
+}
+
+func (obj *Comment) Line() string {
+	return obj.Prefix + obj.Value
+}
+
+func (obj *Comment) Fulln() string {
+	return obj.Full() + endOfLine
+}
+
+func (obj *Comment) Type() TElement {
+	return TComment
+}
+
+func (obj *Comment) Indent() string {
+	return obj.Prefix
+}
diff --git a/types/common.go b/types/common.go
new file mode 100644
index 0000000..b7ea8ea
--- /dev/null
+++ b/types/common.go
@@ -0,0 +1,50 @@
+package types
+
+import (
+	"runtime"
+)
+
+type TElement int
+
+const (
+	TDeleted   TElement = 0
+	TComment   TElement = 1
+	TEmptyLine TElement = 2
+	TKeyValue  TElement = 3
+	TSection   TElement = 4
+	TTrash     TElement = 5
+)
+
+var (
+	endOfLine string = "\n"
+	existing  bool   = false
+)
+
+func SetEndOfLineNative() {
+	switch os := runtime.GOOS; os {
+	case "windows":
+		SetEndOfLineWindows()
+	default:
+		SetEndOfLineUnix()
+	}
+}
+
+func SetEndOfLineUnix() {
+	endOfLine = "\n"
+}
+
+func SetEndOfLineWindows() {
+	endOfLine = "\r\n"
+}
+
+func SetExistingMode(value bool) {
+	existing = value
+}
+
+func createIfNotExist() bool {
+	return !existing
+}
+
+func failIfNotExist() bool {
+	return existing
+}
diff --git a/types/deleted.go b/types/deleted.go
new file mode 100644
index 0000000..02327f0
--- /dev/null
+++ b/types/deleted.go
@@ -0,0 +1,24 @@
+package types
+
+type Deleted struct {
+}
+
+func (obj *Deleted) Full() string {
+	return ""
+}
+
+func (obj *Deleted) Line() string {
+	return ""
+}
+
+func (obj *Deleted) Fulln() string {
+	return ""
+}
+
+func (obj *Deleted) Type() TElement {
+	return TDeleted
+}
+
+func (obj *Deleted) Indent() string {
+	return ""
+}
diff --git a/types/element.go b/types/element.go
new file mode 100644
index 0000000..bf12d9c
--- /dev/null
+++ b/types/element.go
@@ -0,0 +1,9 @@
+package types
+
+type Element interface {
+	Full() string
+	Fulln() string
+	Line() string
+	Indent() string
+	Type() TElement
+}
diff --git a/types/emptyline.go b/types/emptyline.go
new file mode 100644
index 0000000..9cfb7ef
--- /dev/null
+++ b/types/emptyline.go
@@ -0,0 +1,25 @@
+package types
+
+type EmptyLine struct {
+	Prefix string
+}
+
+func (obj *EmptyLine) Full() string {
+	return obj.Prefix
+}
+
+func (obj *EmptyLine) Line() string {
+	return obj.Prefix
+}
+
+func (obj *EmptyLine) Fulln() string {
+	return obj.Full() + endOfLine
+}
+
+func (obj *EmptyLine) Type() TElement {
+	return TEmptyLine
+}
+
+func (obj *EmptyLine) Indent() string {
+	return obj.Prefix
+}
diff --git a/types/ini.go b/types/ini.go
new file mode 100644
index 0000000..518810b
--- /dev/null
+++ b/types/ini.go
@@ -0,0 +1,152 @@
+package types
+
+import (
+	"errors"
+	"strings"
+)
+
+type Ini struct {
+	Sections []Element
+}
+
+func (obj *Ini) Init() {
+	obj.Sections = append(obj.Sections, &Section{}) // global section
+}
+
+func (obj *Ini) Full() string {
+	var body strings.Builder
+	for _, line := range obj.Sections {
+		body.WriteString(line.Fulln())
+	}
+	return body.String()
+}
+
+func (obj *Ini) FindSection(name string) (*Section, error) {
+	for i, sect := range obj.Sections {
+		if sect.(*Section).Name == name {
+			return obj.Sections[i].(*Section), nil
+		}
+	}
+	return nil, errors.New("Section not found: " + name)
+}
+
+func (obj *Ini) DelSection(name string) error {
+	gotIt := false
+	for i, sect := range obj.Sections {
+		if sect.Type() == TSection &&
+			sect.(*Section).Name == name {
+			obj.Sections[i] = &Deleted{}
+			gotIt = true
+		}
+	}
+	if gotIt {
+		return nil
+	} else if failIfNotExist() {
+		return errors.New("Section not found: " + name)
+	} else {
+		return nil
+	}
+}
+
+func (obj *Ini) Get() string {
+	var sectList strings.Builder
+	for _, sect := range obj.Sections {
+		name := sect.(*Section).Name
+		if name != "" || len(sect.(*Section).Lines) > 0 {
+			sectList.WriteString(name + endOfLine)
+		}
+	}
+	return strings.TrimSuffix(sectList.String(), endOfLine)
+}
+
+func (obj *Ini) GetSection(section string) (string, error) {
+	sect, err := obj.FindSection(section)
+	if err != nil {
+		return "", err
+	} else {
+		return sect.Full(), nil
+	}
+}
+
+func (obj *Ini) GetKey(section, key string) (string, error) {
+	sect, err := obj.FindSection(section)
+	if err != nil {
+		return "", err
+	} else {
+		return sect.GetKey(key)
+	}
+}
+
+func (obj *Ini) GetKeyVal(section, key, value string) error {
+	sect, err := obj.FindSection(section)
+	if err != nil {
+		return err
+	} else {
+		return sect.GetKeyVal(key, value)
+	}
+}
+
+func (obj *Ini) AddSection(section string) *Section {
+	sect, err := obj.FindSection(section)
+	if err != nil {
+		var newSection Section
+		newSection.Name = section
+		newSection.Prefix = obj.Sections[len(obj.Sections)-1].Indent()
+		sect = &newSection
+		obj.Sections = append(obj.Sections, sect)
+	}
+	return sect
+}
+
+func (obj *Ini) SetSection(section string) *Section {
+	return obj.AddSection(section)
+}
+
+func (obj *Ini) AddKey(section, key, value string) error {
+	sect, err := obj.FindSection(section)
+	if err != nil {
+		if createIfNotExist() {
+			sect = obj.AddSection(section)
+		} else {
+			return err
+		}
+	}
+	sect.AddKey(key, value)
+	return nil
+}
+
+func (obj *Ini) SetKey(section, key, value string) error {
+	sect, err := obj.FindSection(section)
+	if err != nil {
+		if createIfNotExist() {
+			sect = obj.AddSection(section)
+		} else {
+			return err
+		}
+	}
+	return sect.SetKey(key, value)
+}
+
+func (obj *Ini) DelKey(section, key string) error {
+	sect, err := obj.FindSection(section)
+	if err != nil {
+		if failIfNotExist() {
+			return err
+		} else {
+			return nil
+		}
+	}
+	return sect.DelKey(key)
+}
+
+func (obj *Ini) DelKeyVal(section, key, value string) error {
+	sect, err := obj.FindSection(section)
+	if err != nil {
+		if failIfNotExist() {
+			return err
+		} else {
+			return nil
+		}
+	}
+	return sect.DelKeyVal(key, value)
+}
diff --git a/types/keyvalue.go b/types/keyvalue.go
new file mode 100644
index 0000000..5339fd0
--- /dev/null
+++ b/types/keyvalue.go
@@ -0,0 +1,38 @@
+package types
+
+type KeyValue struct {
+	PrefixKey    string
+	Key          string
+	PostfixKey   string
+	PrefixValue  string
+	Value        string
+	PostfixValue string
+	Comment      Comment
+}
+
+func (obj *KeyValue) Full() string {
+	return obj.PrefixKey +
+		obj.Key +
+		obj.PostfixKey +
+		"=" +
+		obj.PrefixValue +
+		obj.Value +
+		obj.PostfixValue +
+		obj.Comment.Full()
+}
+
+func (obj *KeyValue) Line() string {
+	return obj.Full()
+}
+
+func (obj *KeyValue) Fulln() string {
+	return obj.Full() + endOfLine
+}
+
+func (obj *KeyValue) Type() TElement {
+	return TKeyValue
+}
+
+func (obj *KeyValue) Indent() string {
+	return obj.PrefixKey
+}
diff --git a/types/section.go b/types/section.go
new file mode 100644
index 0000000..b67c337
--- /dev/null
+++ b/types/section.go
@@ -0,0 +1,185 @@
+package types
+
+import (
+	"errors"
+	"strings"
+)
+
+type Section struct {
+	Prefix  string
+	Name    string
+	Postfix string
+	Comment Comment
+	Lines   []Element
+}
+
+func (obj *Section) Headern() string {
+	if obj.Name == "" {
+		return ""
+	} else {
+		return obj.Prefix + "[" + obj.Name + "]" + obj.Postfix + obj.Comment.Full() + endOfLine
+	}
+}
+
+func (obj *Section) Line() string {
+	return obj.Header()
+}
+
+func (obj *Section) Header() string {
+	return strings.TrimSuffix(obj.Headern(), endOfLine)
+}
+
+func (obj *Section) Fulln() string {
+	var body strings.Builder
+	for _, line := range obj.Lines {
+		body.WriteString(line.Fulln())
+	}
+	return obj.Headern() + body.String()
+}
+
+func (obj *Section) Full() string {
+	return strings.TrimSuffix(obj.Fulln(), endOfLine)
+}
+
+func (obj *Section) Type() TElement {
+	return TSection
+}
+
+func (obj *Section) Indent() string {
+	return obj.Prefix
+}
+
+func (obj *Section) DelKey(name string) error {
+	gotIt := false
+	for i, keyVal := range obj.Lines {
+		if keyVal.Type() == TKeyValue &&
+			keyVal.(*KeyValue).Key == name {
+			obj.Lines[i] = &Deleted{}
+			gotIt = true
+		}
+	}
+	if gotIt {
+		return nil
+	} else if failIfNotExist() {
+		return errors.New("Parameter not found: " + name)
+	} else {
+		return nil
+	}
+}
+
+func (obj *Section) DelKeyVal(name, value string) error {
+	gotIt := false
+	for i, keyVal := range obj.Lines {
+		if keyVal.Type() == TKeyValue &&
+			keyVal.(*KeyValue).Key == name &&
+			keyVal.(*KeyValue).Value == value {
+			obj.Lines[i] = &Deleted{}
+			gotIt = true
+		}
+	}
+	if gotIt {
+		return nil
+	} else if failIfNotExist() {
+		return errors.New("Parameter:value pair not found: " + name + ":" + value)
+	} else {
+		return nil
+	}
+}
+
+func (obj *Section) GetKey(name string) (string, error) {
+	var err error = nil
+	var result strings.Builder
+	for _, keyVal := range obj.Lines {
+		if keyVal.Type() == TKeyValue && keyVal.(*KeyValue).Key == name {
+			result.WriteString(keyVal.(*KeyValue).Value + endOfLine)
+		}
+	}
+	if result.String() == "" {
+		err = errors.New("Parameter not found: " + name)
+	}
+	return strings.TrimSuffix(result.String(), endOfLine), err
+}
+
+func (obj *Section) GetKeyVal(name, value string) error {
+	for _, keyVal := range obj.Lines {
+		if keyVal.Type() == TKeyValue &&
+			keyVal.(*KeyValue).Key == name &&
+			keyVal.(*KeyValue).Value == value {
+			return nil
+		}
+	}
+	return errors.New("Parameter:Value not found: " + name + ":" + value)
+}
+
+func (obj *Section) appendKey(name, value string) {
+	var newKeyValue KeyValue
+	var replaceIndex int = -1
+	newKeyValue.Key = name
+	newKeyValue.Value = value
+	// replace first emptyline
+	for i := len(obj.Lines) - 1; i >= 0; i-- {
+		if obj.Lines[i].Type() == TEmptyLine {
+			replaceIndex = i
+		} else {
+			break
+		}
+	}
+	// for right indent and tabs
+	for i := len(obj.Lines) - 1; i >= 0; i-- {
+		if obj.Lines[i].Type() == TKeyValue {
+			template := obj.Lines[i].(*KeyValue)
+			newKeyValue.PrefixKey = template.PrefixKey
+			newKeyValue.PostfixKey = template.PostfixKey
+			newKeyValue.PrefixValue = template.PrefixValue
+			newKeyValue.PostfixValue = template.PostfixValue
+			break
+		}
+	}
+	if replaceIndex == -1 {
+		obj.Lines = append(obj.Lines, &newKeyValue)
+	} else {
+		obj.Lines = append(obj.Lines, obj.Lines[replaceIndex])
+		obj.Lines[replaceIndex] = &newKeyValue
+	}
+}
+
+func (obj *Section) AddKey(name, value string) {
+	gotIt := false
+	for i, keyVal := range obj.Lines {
+		if keyVal.Type() == TKeyValue &&
+			keyVal.(*KeyValue).Key == name &&
+			keyVal.(*KeyValue).Value == value {
+			if !gotIt {
+				gotIt = true
+			} else {
+				obj.Lines[i] = &Deleted{}
+			}
+		}
+	}
+	if !gotIt {
+		obj.appendKey(name, value)
+	}
+}
+
+func (obj *Section) SetKey(name, value string) error {
+	gotIt := false
+	for i, keyVal := range obj.Lines {
+		if keyVal.Type() == TKeyValue &&
+			keyVal.(*KeyValue).Key == name {
+			if !gotIt {
+				keyVal.(*KeyValue).Value = value
+				gotIt = true
+			} else {
+				obj.Lines[i] = &Deleted{}
+			}
+		}
+	}
+	if !gotIt {
+		if createIfNotExist() {
+			obj.appendKey(name, value)
+		} else {
+			return errors.New("Parameter not found: " + name)
+		}
+	}
+	return nil
+}
diff --git a/types/trash.go b/types/trash.go
new file mode 100644
index 0000000..c818fb1
--- /dev/null
+++ b/types/trash.go
@@ -0,0 +1,25 @@
+package types
+
+type Trash struct {
+	Value string
+}
+
+func (obj *Trash) Full() string {
+	return obj.Value
+}
+
+func (obj *Trash) Line() string {
+	return obj.Value
+}
+
+func (obj *Trash) Fulln() string {
+	return obj.Full() + endOfLine
+}
+
+func (obj *Trash) Type() TElement {
+	return TTrash
+}
+
+func (obj *Trash) Indent() string {
+	return ""
+}
diff --git a/writer.go b/writer.go
new file mode 100644
index 0000000..e214bde
--- /dev/null
+++ b/writer.go
@@ -0,0 +1,46 @@
+package main
+
+import (
+	"bufio"
+	"io/ioutil"
+	"os"
+
+	"multini/types"
+)
+
+func replaceOriginal(oldFile, newFile string) error {
+	err := os.Remove(oldFile)
+	if err == nil {
+		err = os.Rename(newFile, oldFile)
+	}
+	return err
+}
+
+func iniWrite(filename string, ini *types.Ini) error {
+	tmpFile, err := ioutil.TempFile(os.TempDir(), "multini")
+	if err == nil {
+		datawriter := bufio.NewWriter(tmpFile)
+		_, err = datawriter.WriteString(ini.Full())
+		if err == nil {
+			err = datawriter.Flush()
+			tmpFile.Close()
+			if err == nil {
+				err = replaceOriginal(filename, tmpFile.Name())
+			}
+		}
+	}
+	return err
+}
+
+func iniWriteInplace(filename string, ini *types.Ini) error {
+	targetFile, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE, 0644)
+	if err == nil {
+		datawriter := bufio.NewWriter(targetFile)
+		_, err = datawriter.WriteString(ini.Full())
+		if err == nil {
+			err = datawriter.Flush()
+			targetFile.Close()
+		}
+	}
+	return err
+}