Add support for the BROWSER environment variablesupport-for-BROWSER-environment-variable

Allow user-defined URL-opening commands via the BROWSER environment
variable. This enables using a non-default browser, or changing the
browser for a single command.

For example, on Mac:

    $ export BROWSER='open -a Firefox'

Windows:

    > setx BROWSER "start iexplore"

In UNIX environments, the command is run through `$SHELL -c`, or
`/bin/sh` if `$SHELL` is not set. On Windows, it uses `cmd /c`.

Ensure that URLs are properly quoted between UNIX and Windows
environments in `fmtBrowserCmd()`.

1 files changed, 22 insertions, 0 deletions

diff --git a/browser_unix.go b/browser_unix.go
new file mode 100644
index 0000000..30d57db
--- /dev/null
+++ b/browser_unix.go
@@ -0,0 +1,22 @@
+// +build !windows
+
+package browser
+
+import (
+	"fmt"
+	"os"
+)
+
+func shell() (shell, flag string) {
+	shell = os.Getenv("SHELL")
+
+	if shell == "" {
+		shell = "/bin/sh"
+	}
+
+	return shell, "-c"
+}
+
+func fmtBrowserCmd(browser, url string) string {
+	return fmt.Sprintf("%s '%s'", browser, url)
+}