feat: Add custom shell flag option for command execution

man/man1/fzf.1

@@ -907,8 +907,18 @@ e.g. \fBfzf --fish | source\fR
 .TP
 .B FZF_DEFAULT_COMMAND
 Default command to use when input is tty. On *nix systems, fzf runs the command
-with \fB$SHELL -c\fR if \fBSHELL\fR is set, otherwise with \fBsh -c\fR, so in
-this case make sure that the command is POSIX-compliant.
+with \fB$SHELL $FZF_SHELL_FLAG\fR if \fBSHELL\fR and \fBFZF_SHELL_FLAGS\fR are set, otherwise with \fBsh -c\fR.
+
+.TP
+.B FZF_SHELL_FLAG
+Custom flag to pass to the shell when executing commands. If not set, fzf defaults to \fB-c\fR.
+.br
+e.g.
+    \fBSHELL=$(which bun) FZF_SHELL_FLAG="--print" \\
+      fzf --listen \\
+        --bind 'start:reload:(await Bun.$`ls`.text()).trim()' \\
+        --preview 'await fetch(`http://127.0.0.1:${process.env.FZF_PORT}`)'\fR
+
 .TP
 .B FZF_DEFAULT_OPTS
 Default options.

src/terminal.go

@@ -3375,6 +3375,10 @@ func (t *Terminal) Loop() {
 					if len(shell) == 0 {
 						shell = "sh"
 					}
+					shellFlag := os.Getenv("FZF_SHELL_FLAG")
+					if len(shellFlag) == 0 {
+						shellFlag = "-c"
+					}
 					shellPath, err := exec.LookPath(shell)
 					if err == nil {
 						t.tui.Close()
@@ -3390,7 +3394,7 @@ func (t *Terminal) Loop() {
 						*/
 						tui.TtyIn()
 						util.SetStdin(tui.TtyIn())
-						syscall.Exec(shellPath, []string{shell, "-c", command}, os.Environ())
+						syscall.Exec(shellPath, []string{shell, shellFlag, command}, os.Environ())
 					}
 				}
 			case actExecute, actExecuteSilent:

src/util/util_unix.go

@@ -10,18 +10,22 @@ import (
 	"golang.org/x/sys/unix"
 )
 
-// ExecCommand executes the given command with $SHELL
+// ExecCommand executes the given command with $SHELL $FZF_SHELL_FLAG 
 func ExecCommand(command string, setpgid bool) *exec.Cmd {
 	shell := os.Getenv("SHELL")
 	if len(shell) == 0 {
 		shell = "sh"
 	}
-	return ExecCommandWith(shell, command, setpgid)
+	shellFlag := os.Getenv("FZF_SHELL_FLAG")
+	if len(shellFlag) == 0 {
+		shellFlag = "-c"
+	}
+	return ExecCommandWith(shell, shellFlag, command, setpgid)
 }
 
-// ExecCommandWith executes the given command with the specified shell
-func ExecCommandWith(shell string, command string, setpgid bool) *exec.Cmd {
-	cmd := exec.Command(shell, "-c", command)
+// ExecCommandWith executes the given command with the specified shell and flag
+func ExecCommandWith(shell string, shellFlag string, command string, setpgid bool) *exec.Cmd {
+	cmd := exec.Command(shell, shellFlag, command)
 	if setpgid {
 		cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
 	}