diff --git a/CHANGELOG.md b/CHANGELOG.md
index b40b415..3f6ac8f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -31,6 +31,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Adds ability to filter reported temperatures (#92)
 - Command line option to list layouts, paths, colorschemes, hotkeys, and filterable devices
 - Adds ability to write out a configuration file
+- Adds a command for specifying the configuration file to use
 
 ### Changed
 
diff --git a/cmd/gotop/main.go b/cmd/gotop/main.go
index 1cbc50d..25dd5b8 100644
--- a/cmd/gotop/main.go
+++ b/cmd/gotop/main.go
@@ -1,6 +1,8 @@
 package main
 
 import (
+	"bufio"
+	"flag"
 	"fmt"
 	"io"
 	"log"
@@ -18,7 +20,7 @@ import (
 	ui "github.com/gizak/termui/v3"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/shibukawa/configdir"
-	flag "github.com/xxxserxxx/opflag"
+	"github.com/xxxserxxx/opflag"
 
 	"github.com/xxxserxxx/gotop/v4"
 	"github.com/xxxserxxx/gotop/v4/colorschemes"
@@ -50,49 +52,50 @@ var (
 	stderrLogger = log.New(os.Stderr, "", 0)
 )
 
-func parseArgs(conf *gotop.Config) error {
+func parseArgs() error {
 	cds := conf.ConfigDir.QueryFolders(configdir.All)
 	cpaths := make([]string, len(cds))
 	for i, p := range cds {
 		cpaths[i] = p.Path
 	}
-	help := flag.BoolP("help", "h", false, "Show this screen.")
-	color := flag.StringP("color", "c", conf.Colorscheme.Name, "Set a colorscheme.")
-	flag.IntVarP(&conf.GraphHorizontalScale, "graphscale", "S", conf.GraphHorizontalScale, "Graph scale factor, >0")
-	version := flag.BoolP("version", "v", false, "Print version and exit.")
-	versioN := flag.BoolP("", "V", false, "Print version and exit.")
-	flag.BoolVarP(&conf.PercpuLoad, "percpu", "p", conf.PercpuLoad, "Show each CPU in the CPU widget.")
-	flag.BoolVarP(&conf.AverageLoad, "averagecpu", "a", conf.AverageLoad, "Show average CPU in the CPU widget.")
-	fahrenheit := flag.BoolP("fahrenheit", "f", conf.TempScale == 'F', "Show temperatures in fahrenheit.Show temperatures in fahrenheit.")
-	flag.BoolVarP(&conf.Statusbar, "statusbar", "s", conf.Statusbar, "Show a statusbar with the time.")
-	flag.DurationVarP(&conf.UpdateInterval, "rate", "r", conf.UpdateInterval, "Number of times per second to update CPU and Mem widgets.")
-	flag.StringVarP(&conf.Layout, "layout", "l", conf.Layout, `Name of layout spec file for the UI. Use "-" to pipe.`)
-	flag.StringVarP(&conf.NetInterface, "interface", "i", "all", "Select network interface. Several interfaces can be defined using comma separated values. Interfaces can also be ignored using `!`")
-	flag.StringVarP(&conf.ExportPort, "export", "x", conf.ExportPort, "Enable metrics for export on the specified port.")
-	flag.BoolVarP(&conf.Mbps, "mbps", "", conf.Mbps, "Show network rate as mbps.")
+	help := opflag.BoolP("help", "h", false, "Show this screen.")
+	color := opflag.StringP("color", "c", conf.Colorscheme.Name, "Set a colorscheme.")
+	opflag.IntVarP(&conf.GraphHorizontalScale, "graphscale", "S", conf.GraphHorizontalScale, "Graph scale factor, >0")
+	version := opflag.BoolP("version", "v", false, "Print version and exit.")
+	versioN := opflag.BoolP("", "V", false, "Print version and exit.")
+	opflag.BoolVarP(&conf.PercpuLoad, "percpu", "p", conf.PercpuLoad, "Show each CPU in the CPU widget.")
+	opflag.BoolVarP(&conf.AverageLoad, "averagecpu", "a", conf.AverageLoad, "Show average CPU in the CPU widget.")
+	fahrenheit := opflag.BoolP("fahrenheit", "f", conf.TempScale == 'F', "Show temperatures in fahrenheit.Show temperatures in fahrenheit.")
+	opflag.BoolVarP(&conf.Statusbar, "statusbar", "s", conf.Statusbar, "Show a statusbar with the time.")
+	opflag.DurationVarP(&conf.UpdateInterval, "rate", "r", conf.UpdateInterval, "Number of times per second to update CPU and Mem widgets.")
+	opflag.StringVarP(&conf.Layout, "layout", "l", conf.Layout, `Name of layout spec file for the UI. Use "-" to pipe.`)
+	opflag.StringVarP(&conf.NetInterface, "interface", "i", "all", "Select network interface. Several interfaces can be defined using comma separated values. Interfaces can also be ignored using `!`")
+	opflag.StringVarP(&conf.ExportPort, "export", "x", conf.ExportPort, "Enable metrics for export on the specified port.")
+	opflag.BoolVarP(&conf.Mbps, "mbps", "", conf.Mbps, "Show network rate as mbps.")
 	// FIXME Where did this go??
-	//conf.Band = flag.IntP("bandwidth", "B", 100, "Specify the number of bits per seconds.")
-	flag.BoolVar(&conf.Test, "test", conf.Test, "Runs tests and exits with success/failure code.")
-	list := flag.String("list", "", `List <devices|layouts|colorschemes|paths|keys>
+	//conf.Band = opflag.IntP("bandwidth", "B", 100, "Specify the number of bits per seconds.")
+	opflag.BoolVar(&conf.Test, "test", conf.Test, "Runs tests and exits with success/failure code.")
+	opflag.StringP("", "C", "", "Config file to use instead of default (MUST BE FIRST ARGUMENT)")
+	list := opflag.String("list", "", `List <devices|layouts|colorschemes|paths|keys>
          devices: Prints out device names for filterable widgets
          layouts: Lists build-in layouts
          colorschemes: Lists built-in colorschemes
          paths: List out configuration file search paths
-		 widgets: Widgets that can be used in a layout
+         widgets: Widgets that can be used in a layout
          keys: Show the keyboard bindings.`)
-	wc := flag.Bool("write-config", false, "Write out a default config file.")
-	flag.SortFlags = false
-	flag.Usage = func() {
+	wc := opflag.Bool("write-config", false, "Write out a default config file.")
+	opflag.SortFlags = false
+	opflag.Usage = func() {
 		fmt.Fprintf(os.Stderr, "Usage: %s [options]\n\nOptions:\n", os.Args[0])
-		flag.PrintDefaults()
+		opflag.PrintDefaults()
 	}
-	flag.Parse()
+	opflag.Parse()
 	if *version || *versioN {
 		fmt.Printf("gotop %s (%s)\n", Version, BuildDate)
 		os.Exit(0)
 	}
 	if *help {
-		flag.Usage()
+		opflag.Usage()
 		os.Exit(0)
 	}
 	cs, err := colorschemes.FromName(conf.ConfigDir, *color)
@@ -331,14 +334,17 @@ func eventLoop(c gotop.Config, grid *layout.MyGrid) {
 	}
 }
 
-// TODO: Add fans
-// TODO: mpd visualizer widget
+// TODO: @devices fans
+// TODO: @devices mpd visualizer
+// TODO: @devices color bars for memory, a-la bashtop
 // TODO: Add tab completion for Linux https://gist.github.com/icholy/5314423
 // TODO: state:merge #135 linux console font (cmatsuoka/console-font)
 // TODO: Abstract out the UI toolkit.  mum4k/termdash, VladimirMarkelov/clui, gcla/gowid, rivo/tview, marcusolsson/tui-go might work better for some OS/Archs. Performance/memory use comparison would be interesting.
-// TODO: all of the go vet stuff, more unit tests, benchmarks, finish remote.
-// TODO: color bars for memory, a-la bashtop
+// TODO: more unit tests, benchmarks
+// TODO: README is getting long. Move to wiki.
 // TODO: add verbose debugging option
+// TODO: find VMs for FreeBSD, etc for testing gotop
+// TODO: add README about extensions, and wiki page for writing extensions
 func main() {
 	// For performance testing
 	//go func() {
@@ -359,15 +365,23 @@ func main() {
 }
 
 func run() int {
-	conf := gotop.NewConfig()
+	conf = gotop.NewConfig()
 	// Find the config file; look in (1) local, (2) user, (3) global
+	// Check the last argument first
+	fs := flag.NewFlagSet("config", flag.ContinueOnError)
+	cfg := fs.String("C", "", "Config file")
+	fs.SetOutput(bufio.NewWriter(nil))
+	fs.Parse(os.Args[1:])
+	if *cfg != "" {
+		conf.ConfigFile = *cfg
+	}
 	err := conf.Load()
 	if err != nil {
 		fmt.Printf("failed to parse config file: %s\n", err)
 		return 2
 	}
 	// Override with command line arguments
-	err = parseArgs(&conf)
+	err = parseArgs()
 	if err != nil {
 		fmt.Printf("parsing CLI args: %s\n", err)
 		return 2
diff --git a/config.go b/config.go
index 6a109e0..0cc5e61 100644
--- a/config.go
+++ b/config.go
@@ -5,7 +5,9 @@ import (
 	"bytes"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"log"
+	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -16,6 +18,9 @@ import (
 	"github.com/xxxserxxx/gotop/v4/widgets"
 )
 
+// CONFFILE is the name of the default config file
+const CONFFILE = "gotop.conf"
+
 type Config struct {
 	ConfigDir            configdir.ConfigDir
 	GraphHorizontalScale int
@@ -34,6 +39,7 @@ type Config struct {
 	Temps                []string
 	Test                 bool
 	ExtensionVars        map[string]string
+	ConfigFile           string
 }
 
 func NewConfig() Config {
@@ -54,21 +60,25 @@ func NewConfig() Config {
 		ExtensionVars:        make(map[string]string),
 	}
 	conf.Colorscheme, _ = colorschemes.FromName(conf.ConfigDir, "default")
+	folder := conf.ConfigDir.QueryFolderContainsFile(CONFFILE)
+	if folder != nil {
+		conf.ConfigFile = filepath.Join(folder.Path, CONFFILE)
+	}
 	return conf
 }
 
 func (conf *Config) Load() error {
 	var in []byte
-	var err error
-	cfn := "gotop.conf"
-	folder := conf.ConfigDir.QueryFolderContainsFile(cfn)
-	if folder != nil {
-		if in, err = folder.ReadFile(cfn); err != nil {
-			return err
-		}
-	} else {
+	if conf.ConfigFile == "" {
 		return nil
 	}
+	var err error
+	if _, err = os.Stat(conf.ConfigFile); os.IsNotExist(err) {
+		return nil
+	}
+	if in, err = ioutil.ReadFile(conf.ConfigFile); err != nil {
+		return err
+	}
 	return load(bytes.NewReader(in), conf)
 }
 
@@ -169,21 +179,35 @@ func load(in io.Reader, conf *Config) error {
 	return nil
 }
 
+// Write serializes the configuration to a file.
+// The configuration written is based on the loaded configuration, plus any
+// command-line changes, so it can be used to update an existing configuration
+// file.  The file will be written to the specificed `--config` argument file,
+// if one is set; otherwise, it'll create one in the user's config directory.
 func (conf *Config) Write() (string, error) {
-	cfn := "gotop.conf"
-	ds := conf.ConfigDir.QueryFolders(configdir.Global)
-	if len(ds) == 0 {
-		ds = conf.ConfigDir.QueryFolders(configdir.Local)
+	var dir *configdir.Config
+	var file string = CONFFILE
+	if conf.ConfigFile == "" {
+		ds := conf.ConfigDir.QueryFolders(configdir.Global)
 		if len(ds) == 0 {
-			return "", fmt.Errorf("error locating config folders")
+			ds = conf.ConfigDir.QueryFolders(configdir.Local)
+			if len(ds) == 0 {
+				return "", fmt.Errorf("error locating config folders")
+			}
 		}
+		ds[0].CreateParentDir(CONFFILE)
+		dir = ds[0]
+	} else {
+		dir = &configdir.Config{}
+		dir.Path = filepath.Dir(conf.ConfigFile)
+		file = filepath.Base(conf.ConfigFile)
 	}
 	marshalled := marshal(conf)
-	err := ds[0].WriteFile(cfn, marshalled)
+	err := dir.WriteFile(file, marshalled)
 	if err != nil {
 		return "", err
 	}
-	return filepath.Join(ds[0].Path, cfn), nil
+	return filepath.Join(dir.Path, file), nil
 }
 
 func marshal(c *Config) []byte {
diff --git a/go.mod b/go.mod
index 29a5919..d0867eb 100644
--- a/go.mod
+++ b/go.mod
@@ -14,7 +14,7 @@ require (
 	github.com/shirou/w32 v0.0.0-20160930032740-bb4de0191aa4 // indirect
 	github.com/stretchr/testify v1.4.0
 	github.com/xxxserxxx/iSMC v1.0.1
-	github.com/xxxserxxx/opflag v1.0.3
+	github.com/xxxserxxx/opflag v1.0.5
 	golang.org/x/sync v0.0.0-20200317015054-43a5402ce75a // indirect
 	golang.org/x/tools v0.0.0-20200425043458-8463f397d07c // indirect
 	golang.org/x/tools/gopls v0.4.0 // indirect
diff --git a/go.sum b/go.sum
index 2410a27..f165c4a 100644
--- a/go.sum
+++ b/go.sum
@@ -119,6 +119,10 @@ github.com/xxxserxxx/opflag v1.0.2 h1:TanW4Ck/RNal4fP2VVAvhEu7eBq4z+9hhGq9Q8OTq6
 github.com/xxxserxxx/opflag v1.0.2/go.mod h1:GWZtb3/tGGj5W1GE/JTyJAuqgxDxl1+jqDGAGM+P/p4=
 github.com/xxxserxxx/opflag v1.0.3 h1:ugsBWZtSXUaMLEjPLW0WKGjq/gsrc0GpZYbCJY6ZHVY=
 github.com/xxxserxxx/opflag v1.0.3/go.mod h1:GWZtb3/tGGj5W1GE/JTyJAuqgxDxl1+jqDGAGM+P/p4=
+github.com/xxxserxxx/opflag v1.0.4 h1:g979b8oReAERfDKFTTwdvAYIarFxpVYOzYrHa/hMvNs=
+github.com/xxxserxxx/opflag v1.0.4/go.mod h1:GWZtb3/tGGj5W1GE/JTyJAuqgxDxl1+jqDGAGM+P/p4=
+github.com/xxxserxxx/opflag v1.0.5 h1:2H4Qtl1qe+dSkEcGt+fBe2mQ8z14MgkWPqcLaoa6k90=
+github.com/xxxserxxx/opflag v1.0.5/go.mod h1:GWZtb3/tGGj5W1GE/JTyJAuqgxDxl1+jqDGAGM+P/p4=
 github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 golang.org/x/arch v0.0.0-20181203225421-5a4828bb7045/go.mod h1:cYlCBUl1MsqxdiKgmc4uh7TxZfWSFLOGSRR090WDxt8=
 golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
diff --git a/widgets/temp.go b/widgets/temp.go
index 05ad3c1..f2b0f93 100644
--- a/widgets/temp.go
+++ b/widgets/temp.go
@@ -31,7 +31,6 @@ type TempWidget struct {
 	tempsMetric    map[string]prometheus.Gauge
 }
 
-// TODO: state:deferred 156 Added temperatures for NVidia GPUs (azak-azkaran/master). Crashes on non-nvidia machines.
 func NewTempWidget(tempScale TempScale, filter []string) *TempWidget {
 	self := &TempWidget{
 		Block:          ui.NewBlock(),