A random set of fixes (#1600)

crates/nu-cli/src/commands/classified/external.rs

@@ -444,6 +444,8 @@ fn spawn(
             process.arg("/c");
             process.arg(&command.name);
             for arg in args {
+                // Clean the args before we use them:
+                let arg = arg.replace("|", "\\|");
                 process.arg(&arg);
             }
             process

crates/nu-cli/src/commands/help.rs

@@ -76,6 +76,12 @@ impl PerItemCommand for Help {
                     return Ok(
                         get_help(&command.name(), &command.usage(), command.signature()).into(),
                     );
+                } else {
+                    return Err(ShellError::labeled_error(
+                        "Can't find command (use 'help commands' for full list)",
+                        "can't find command",
+                        tag,
+                    ));
                 }
                 let help = futures::stream::iter(help);
                 Ok(help.to_output_stream())