add an option to configure shell used by commands

app.go

@@ -16,7 +16,7 @@ type App struct {
 func waitKey() error {
 	// TODO: this should be done with termbox somehow
 
-	cmd := exec.Command(envShell, "-c", "echo; echo -n 'Press any key to continue'; stty -echo; read -n 1; stty echo; echo")
+	cmd := exec.Command(gOpts.shell, "-c", "echo; echo -n 'Press any key to continue'; stty -echo; read -n 1; stty echo; echo")
 
 	cmd.Stdin = os.Stdin
 	cmd.Stdout = os.Stdout
@@ -98,7 +98,7 @@ func (app *App) runShell(s string, args []string, wait bool, async bool) {
 	}
 
 	args = append([]string{"-c", s, "--"}, args...)
-	cmd := exec.Command(envShell, args...)
+	cmd := exec.Command(gOpts.shell, args...)
 
 	if !async {
 		cmd.Stdin = os.Stdin

comp.go

@@ -11,16 +11,18 @@ import (
 var (
 	gCmdWords = []string{"set", "map", "cmd"}
 	gOptWords = []string{
-		"preview",
-		"nopreview",
-		"preview!",
 		"hidden",
 		"nohidden",
 		"hidden!",
-		"tabstop",
+		"preview",
+		"nopreview",
+		"preview!",
 		"scrolloff",
-		"sortby",
+		"tabstop",
+		"ifs",
+		"shell",
 		"showinfo",
+		"sortby",
 		"ratios",
 	}
 )

doc/reference.md

@@ -23,12 +23,14 @@
 
 ## Options
 
-    preview    bool    (default on)
     hidden     bool    (default off)
-    tabstop    int     (default 8)
+    preview    bool    (default on)
     scrolloff  int     (default 0)
-    sortby     string  (default name)
+    tabstop    int     (default 8)
+    ifs        string  (default not set)
+    shell      string  (default $SHELL)
     showinfo   string  (default none)
+    sortby     string  (default name)
     ratios     string  (default 1:2:3)
 
 ## Variables

etc/lfrc.example

@@ -5,6 +5,13 @@
 #set nopreview
 #set showinfo size
 
+# Some systems use more efficient shell implementations for non-interactive use
+# (e.g. `dash`) mapped to `/bin/sh`. By setting this option here we can tell
+# `lf` to use this implementation for shell commands. This can decrease the
+# startup times of commands but may also change the syntax that you are used to
+# (e.g. non-POSIX features provided by your regular shell).
+set shell /bin/sh
+
 # leave some space at the top and the bottom of the screen
 set scrolloff 10
 

eval.go

@@ -62,6 +62,8 @@ func (e *SetExpr) eval(app *App, args []string) {
 		gOpts.tabstop = n
 	case "ifs":
 		gOpts.ifs = e.val
+	case "shell":
+		gOpts.shell = e.val
 	case "showinfo":
 		if e.val != "none" && e.val != "size" && e.val != "time" {
 			msg := "showinfo should either be 'none', 'size' or 'time'"

opts.go

@@ -6,6 +6,7 @@ type Opts struct {
 	scrolloff int
 	tabstop   int
 	ifs       string
+	shell     string
 	showinfo  string
 	sortby    string
 	ratios    []int
@@ -21,6 +22,7 @@ func init() {
 	gOpts.scrolloff = 0
 	gOpts.tabstop = 8
 	gOpts.ifs = ""
+	gOpts.shell = envShell
 	gOpts.showinfo = "none"
 	gOpts.sortby = "name"
 	gOpts.ratios = []int{1, 2, 3}