cli · vilmibm · Jul 15, 2020 · Jun 12, 2020 · Jul 3, 2020 · Jul 7, 2020
@@ -6,6 +6,7 @@ import (
 	"io"
 	"net"
 	"os"
+	"os/exec"
 	"path"
 	"strings"
 
@@ -40,11 +41,26 @@ func main() {
 	cmd, _, err := command.RootCmd.Traverse(expandedArgs)
 	if err != nil || cmd == command.RootCmd {
 		originalArgs := expandedArgs
-		expandedArgs, err = command.ExpandAlias(os.Args)
+		expandedArgs, isShell, err := command.ExpandAlias(os.Args)
 		if err != nil {
 			fmt.Fprintf(stderr, "failed to process aliases:  %s\n", err)
 			os.Exit(2)
 		}
+
+		if isShell {
+			err = command.ExecuteShellAlias(expandedArgs)
+			if err != nil {
+				if ee, ok := err.(*exec.ExitError); ok {
+					os.Exit(ee.ExitCode())
+				}
+
+				fmt.Fprintf(stderr, "failed to run external command: %s", err)
+				os.Exit(3)
+			}
+
+			os.Exit(0)
+		}
+
 		if hasDebug {
 			fmt.Fprintf(stderr, "%v -> %v\n", originalArgs, expandedArgs)
 		}

@@ -16,21 +16,39 @@ func init() {
 	aliasCmd.AddCommand(aliasSetCmd)
 	aliasCmd.AddCommand(aliasListCmd)
 	aliasCmd.AddCommand(aliasDeleteCmd)
+
+	aliasSetCmd.Flags().BoolP("shell", "s", false, "Declare an alias to be passed through a shell interpreter")
 }
 
 var aliasCmd = &cobra.Command{
 	Use:   "alias",
-	Short: "Create shortcuts for gh commands",
+	Short: "Create command shortcuts",
+	Long: heredoc.Doc(`
+	Aliases can be used to make shortcuts for gh commands or to compose multiple commands.
+
+	Run "gh help alias set" to learn more.
+	`),
 }
 
 var aliasSetCmd = &cobra.Command{
 	Use:   "set <alias> <expansion>",
 	Short: "Create a shortcut for a gh command",
-	Long: `Declare a word as a command alias that will expand to the specified command.
+	Long: heredoc.Doc(`
+	Declare a word as a command alias that will expand to the specified command(s).
+
+	The expansion may specify additional arguments and flags. If the expansion
+	includes positional placeholders such as '$1', '$2', etc., any extra arguments
+	that follow the invocation of an alias will be inserted appropriately.
+
+	If '--shell' is specified, the alias will be run through a shell interpreter (sh). This allows you
+	to compose commands with "|" or redirect with ">". Note that extra arguments following the alias
+	will not be automatically passed to the expanded expression. To have a shell alias receive
+	arguments, you must explicitly accept them using "$1", "$2", etc., or "$@" to accept all of them.
+
+	Platform note: on Windows, shell aliases are executed via "sh" as installed by Git For Windows. If
+	you have installed git on Windows in some other way, shell aliases may not work for you.
 
-The expansion may specify additional arguments and flags. If the expansion
-includes positional placeholders such as '$1', '$2', etc., any extra arguments
-that follow the invocation of an alias will be inserted appropriately.`,
+	Quotes must always be used when defining a command as in the examples.`),
 	Example: heredoc.Doc(`
 	$ gh alias set pv 'pr view'
 	$ gh pv -w 123
@@ -41,13 +59,12 @@ that follow the invocation of an alias will be inserted appropriately.`,
 	$ gh alias set epicsBy 'issue list --author="$1" --label="epic"'
 	$ gh epicsBy vilmibm
 	#=> gh issue list --author="vilmibm" --label="epic"
-	`),
-	Args: cobra.MinimumNArgs(2),
-	RunE: aliasSet,
 
-	// NB: this allows a user to eschew quotes when specifying an alias expansion. We'll have to
-	// revisit it if we ever want to add flags to alias set but we have no current plans for that.
-	DisableFlagParsing: true,
+	$ gh alias set --shell igrep 'gh issue list --label="$1" | grep $2'
+	$ gh igrep epic foo
+	#=> gh issue list --label="epic" | grep "foo"`),
+	Args: cobra.ExactArgs(2),
+	RunE: aliasSet,
 }
 
 func aliasSet(cmd *cobra.Command, args []string) error {
@@ -63,19 +80,26 @@ func aliasSet(cmd *cobra.Command, args []string) error {
 	}
 
 	alias := args[0]
-	expansion := processArgs(args[1:])
-
-	expansionStr := strings.Join(expansion, " ")
+	expansion := args[1]
 
 	out := colorableOut(cmd)
-	fmt.Fprintf(out, "- Adding alias for %s: %s\n", utils.Bold(alias), utils.Bold(expansionStr))
+	fmt.Fprintf(out, "- Adding alias for %s: %s\n", utils.Bold(alias), utils.Bold(expansion))
+
+	shell, err := cmd.Flags().GetBool("shell")
+	if err != nil {
+		return err
+	}
+	if shell && !strings.HasPrefix(expansion, "!") {
+		expansion = "!" + expansion
+	}
+	isExternal := strings.HasPrefix(expansion, "!")
 
-	if validCommand([]string{alias}) {
+	if validCommand(alias) {
 		return fmt.Errorf("could not create alias: %q is already a gh command", alias)
 	}
 
-	if !validCommand(expansion) {
-		return fmt.Errorf("could not create alias: %s does not correspond to a gh command", utils.Bold(expansionStr))
+	if !isExternal && !validCommand(expansion) {
+		return fmt.Errorf("could not create alias: %s does not correspond to a gh command", expansion)
 	}
 
 	successMsg := fmt.Sprintf("%s Added alias.", utils.Green("✓"))
@@ -86,11 +110,11 @@ func aliasSet(cmd *cobra.Command, args []string) error {
 			utils.Green("✓"),
 			utils.Bold(alias),
 			utils.Bold(oldExpansion),
-			utils.Bold(expansionStr),
+			utils.Bold(expansion),
 		)
 	}
 
-	err = aliasCfg.Add(alias, expansionStr)
+	err = aliasCfg.Add(alias, expansion)
 	if err != nil {
 		return fmt.Errorf("could not create alias: %s", err)
 	}
@@ -100,26 +124,13 @@ func aliasSet(cmd *cobra.Command, args []string) error {
 	return nil
 }
 
-func validCommand(expansion []string) bool {
-	cmd, _, err := RootCmd.Traverse(expansion)
-	return err == nil && cmd != RootCmd
-}
-
-func processArgs(args []string) []string {
-	if len(args) == 1 {
-		split, _ := shlex.Split(args[0])
-		return split
-	}
-
-	newArgs := []string{}
-	for _, a := range args {
-		if !strings.HasPrefix(a, "-") && strings.Contains(a, " ") {
-			a = fmt.Sprintf("%q", a)
-		}
-		newArgs = append(newArgs, a)
+func validCommand(expansion string) bool {
+	split, err := shlex.Split(expansion)
+	if err != nil {
+		return false
 	}
-
-	return newArgs
+	cmd, _, err := RootCmd.Traverse(split)
+	return err == nil && cmd != RootCmd
 }
 
 var aliasListCmd = &cobra.Command{