diff --git a/install/bash.go b/install/bash.go
new file mode 100644
index 0000000..17c64de
--- /dev/null
+++ b/install/bash.go
@@ -0,0 +1,37 @@
+package install
+
+import "fmt"
+
+// (un)install in bash
+// basically adds/remove from .bashrc:
+//
+// complete -C </path/to/completion/command> <command>
+type bash struct {
+	rc string
+}
+
+func (b bash) IsInstalled(cmd, bin string) bool {
+	completeCmd := b.cmd(cmd, bin)
+	return lineInFile(b.rc, completeCmd)
+}
+
+func (b bash) Install(cmd, bin string) error {
+	if b.IsInstalled(cmd, bin) {
+		return fmt.Errorf("already installed in %s", b.rc)
+	}
+	completeCmd := b.cmd(cmd, bin)
+	return appendToFile(b.rc, completeCmd)
+}
+
+func (b bash) Uninstall(cmd, bin string) error {
+	if !b.IsInstalled(cmd, bin) {
+		return fmt.Errorf("does not installed in %s", b.rc)
+	}
+
+	completeCmd := b.cmd(cmd, bin)
+	return removeFromFile(b.rc, completeCmd)
+}
+
+func (bash) cmd(cmd, bin string) string {
+	return fmt.Sprintf("complete -C %s %s", bin, cmd)
+}
diff --git a/install/fish.go b/install/fish.go
new file mode 100644
index 0000000..2b64bfc
--- /dev/null
+++ b/install/fish.go
@@ -0,0 +1,69 @@
+package install
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"path/filepath"
+	"text/template"
+)
+
+// (un)install in fish
+
+type fish struct {
+	configDir string
+}
+
+func (f fish) IsInstalled(cmd, bin string) bool {
+	completionFile := f.getCompletionFilePath(cmd)
+	if _, err := os.Stat(completionFile); err == nil {
+		return true
+	}
+	return false
+}
+
+func (f fish) Install(cmd, bin string) error {
+	if f.IsInstalled(cmd, bin) {
+		return fmt.Errorf("already installed at %s", f.getCompletionFilePath(cmd))
+	}
+
+	completionFile := f.getCompletionFilePath(cmd)
+	completeCmd, err := f.cmd(cmd, bin)
+	if err != nil {
+		return err
+	}
+
+	return createFile(completionFile, completeCmd)
+}
+
+func (f fish) Uninstall(cmd, bin string) error {
+	if !f.IsInstalled(cmd, bin) {
+		return fmt.Errorf("does not installed in %s", f.configDir)
+	}
+
+	completionFile := f.getCompletionFilePath(cmd)
+	return os.Remove(completionFile)
+}
+
+func (f fish) getCompletionFilePath(cmd string) string {
+	return filepath.Join(f.configDir, "completions", fmt.Sprintf("%s.fish", cmd))
+}
+
+func (f fish) cmd(cmd, bin string) (string, error) {
+	var buf bytes.Buffer
+	params := struct{ Cmd, Bin string }{cmd, bin}
+	tmpl := template.Must(template.New("cmd").Parse(`
+function __complete_{{.Cmd}}
+    set -lx COMP_LINE (commandline -cp)
+    test -z (commandline -ct)
+    and set COMP_LINE "$COMP_LINE "
+    {{.Bin}}
+end
+complete -f -c {{.Cmd}} -a "(__complete_{{.Cmd}})"
+`))
+	err := tmpl.Execute(&buf, params)
+	if err != nil {
+		return "", err
+	}
+	return buf.String(), nil
+}
diff --git a/install/install.go b/install/install.go
new file mode 100644
index 0000000..1da52c3
--- /dev/null
+++ b/install/install.go
@@ -0,0 +1,177 @@
+// Package install provide installation functions of command completion.
+package install
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/user"
+	"path/filepath"
+	"runtime"
+	"strings"
+
+	"github.com/hashicorp/go-multierror"
+)
+
+func Run(name string, uninstall, yes bool, out io.Writer, in io.Reader) {
+	action := "install"
+	if uninstall {
+		action = "uninstall"
+	}
+	if !yes {
+		fmt.Fprintf(out, "%s completion for %s? ", action, name)
+		var answer string
+		fmt.Fscanln(in, &answer)
+		switch strings.ToLower(answer) {
+		case "y", "yes":
+		default:
+			fmt.Fprintf(out, "Cancelling...")
+			return
+		}
+	}
+	fmt.Fprintf(out, action+"ing...")
+
+	if uninstall {
+		Uninstall(name)
+	} else {
+		Install(name)
+	}
+}
+
+type installer interface {
+	IsInstalled(cmd, bin string) bool
+	Install(cmd, bin string) error
+	Uninstall(cmd, bin string) error
+}
+
+// Install complete command given:
+// cmd: is the command name
+func Install(cmd string) error {
+	is := installers()
+	if len(is) == 0 {
+		return errors.New("Did not find any shells to install")
+	}
+	bin, err := getBinaryPath()
+	if err != nil {
+		return err
+	}
+
+	for _, i := range is {
+		errI := i.Install(cmd, bin)
+		if errI != nil {
+			err = multierror.Append(err, errI)
+		}
+	}
+
+	return err
+}
+
+// IsInstalled returns true if the completion
+// for the given cmd is installed.
+func IsInstalled(cmd string) bool {
+	bin, err := getBinaryPath()
+	if err != nil {
+		return false
+	}
+
+	for _, i := range installers() {
+		installed := i.IsInstalled(cmd, bin)
+		if installed {
+			return true
+		}
+	}
+
+	return false
+}
+
+// Uninstall complete command given:
+// cmd: is the command name
+func Uninstall(cmd string) error {
+	is := installers()
+	if len(is) == 0 {
+		return errors.New("Did not find any shells to uninstall")
+	}
+	bin, err := getBinaryPath()
+	if err != nil {
+		return err
+	}
+
+	for _, i := range is {
+		errI := i.Uninstall(cmd, bin)
+		if errI != nil {
+			err = multierror.Append(err, errI)
+		}
+	}
+
+	return err
+}
+
+func installers() (i []installer) {
+	// The list of bash config files candidates where it is
+	// possible to install the completion command.
+	var bashConfFiles []string
+	switch runtime.GOOS {
+	case "darwin":
+		bashConfFiles = []string{".bash_profile"}
+	default:
+		bashConfFiles = []string{".bashrc", ".bash_profile", ".bash_login", ".profile"}
+	}
+	for _, rc := range bashConfFiles {
+		if f := rcFile(rc); f != "" {
+			i = append(i, bash{f})
+			break
+		}
+	}
+	if f := rcFile(".zshrc"); f != "" {
+		i = append(i, zsh{f})
+	}
+	if d := fishConfigDir(); d != "" {
+		i = append(i, fish{d})
+	}
+	return
+}
+
+func fishConfigDir() string {
+	configDir := filepath.Join(getConfigHomePath(), "fish")
+	if configDir == "" {
+		return ""
+	}
+	if info, err := os.Stat(configDir); err != nil || !info.IsDir() {
+		return ""
+	}
+	return configDir
+}
+
+func getConfigHomePath() string {
+	u, err := user.Current()
+	if err != nil {
+		return ""
+	}
+
+	configHome := os.Getenv("XDG_CONFIG_HOME")
+	if configHome == "" {
+		return filepath.Join(u.HomeDir, ".config")
+	}
+	return configHome
+}
+
+func getBinaryPath() (string, error) {
+	bin, err := os.Executable()
+	if err != nil {
+		return "", err
+	}
+	return filepath.Abs(bin)
+}
+
+func rcFile(name string) string {
+	u, err := user.Current()
+	if err != nil {
+		return ""
+	}
+	path := filepath.Join(u.HomeDir, name)
+	if _, err := os.Stat(path); err != nil {
+		return ""
+	}
+	return path
+}
diff --git a/install/utils.go b/install/utils.go
new file mode 100644
index 0000000..d34ac8c
--- /dev/null
+++ b/install/utils.go
@@ -0,0 +1,140 @@
+package install
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+)
+
+func lineInFile(name string, lookFor string) bool {
+	f, err := os.Open(name)
+	if err != nil {
+		return false
+	}
+	defer f.Close()
+	r := bufio.NewReader(f)
+	prefix := []byte{}
+	for {
+		line, isPrefix, err := r.ReadLine()
+		if err == io.EOF {
+			return false
+		}
+		if err != nil {
+			return false
+		}
+		if isPrefix {
+			prefix = append(prefix, line...)
+			continue
+		}
+		line = append(prefix, line...)
+		if string(line) == lookFor {
+			return true
+		}
+		prefix = prefix[:0]
+	}
+}
+
+func createFile(name string, content string) error {
+	// make sure file directory exists
+	if err := os.MkdirAll(filepath.Dir(name), 0775); err != nil {
+		return err
+	}
+
+	// create the file
+	f, err := os.Create(name)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	// write file content
+	_, err = f.WriteString(fmt.Sprintf("%s\n", content))
+	return err
+}
+
+func appendToFile(name string, content string) error {
+	f, err := os.OpenFile(name, os.O_RDWR|os.O_APPEND, 0)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	_, err = f.WriteString(fmt.Sprintf("\n%s\n", content))
+	return err
+}
+
+func removeFromFile(name string, content string) error {
+	backup := name + ".bck"
+	err := copyFile(name, backup)
+	if err != nil {
+		return err
+	}
+	temp, err := removeContentToTempFile(name, content)
+	if err != nil {
+		return err
+	}
+
+	err = copyFile(temp, name)
+	if err != nil {
+		return err
+	}
+
+	return os.Remove(backup)
+}
+
+func removeContentToTempFile(name, content string) (string, error) {
+	rf, err := os.Open(name)
+	if err != nil {
+		return "", err
+	}
+	defer rf.Close()
+	wf, err := ioutil.TempFile("/tmp", "complete-")
+	if err != nil {
+		return "", err
+	}
+	defer wf.Close()
+
+	r := bufio.NewReader(rf)
+	prefix := []byte{}
+	for {
+		line, isPrefix, err := r.ReadLine()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return "", err
+		}
+		if isPrefix {
+			prefix = append(prefix, line...)
+			continue
+		}
+		line = append(prefix, line...)
+		str := string(line)
+		if str == content {
+			continue
+		}
+		_, err = wf.WriteString(str + "\n")
+		if err != nil {
+			return "", err
+		}
+		prefix = prefix[:0]
+	}
+	return wf.Name(), nil
+}
+
+func copyFile(src string, dst string) error {
+	in, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer in.Close()
+	out, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+	_, err = io.Copy(out, in)
+	return err
+}
diff --git a/install/zsh.go b/install/zsh.go
new file mode 100644
index 0000000..29950ab
--- /dev/null
+++ b/install/zsh.go
@@ -0,0 +1,44 @@
+package install
+
+import "fmt"
+
+// (un)install in zsh
+// basically adds/remove from .zshrc:
+//
+// autoload -U +X bashcompinit && bashcompinit"
+// complete -C </path/to/completion/command> <command>
+type zsh struct {
+	rc string
+}
+
+func (z zsh) IsInstalled(cmd, bin string) bool {
+	completeCmd := z.cmd(cmd, bin)
+	return lineInFile(z.rc, completeCmd)
+}
+
+func (z zsh) Install(cmd, bin string) error {
+	if z.IsInstalled(cmd, bin) {
+		return fmt.Errorf("already installed in %s", z.rc)
+	}
+
+	completeCmd := z.cmd(cmd, bin)
+	bashCompInit := "autoload -U +X bashcompinit && bashcompinit"
+	if !lineInFile(z.rc, bashCompInit) {
+		completeCmd = bashCompInit + "\n" + completeCmd
+	}
+
+	return appendToFile(z.rc, completeCmd)
+}
+
+func (z zsh) Uninstall(cmd, bin string) error {
+	if !z.IsInstalled(cmd, bin) {
+		return fmt.Errorf("does not installed in %s", z.rc)
+	}
+
+	completeCmd := z.cmd(cmd, bin)
+	return removeFromFile(z.rc, completeCmd)
+}
+
+func (zsh) cmd(cmd, bin string) string {
+	return fmt.Sprintf("complete -o nospace -C %s %s", bin, cmd)
+}