fix(packages/core): pipeStages splits command with >> incorrectly

part of #7413

packages/core/src/models/command.ts

@@ -150,7 +150,12 @@ export interface CommandLine<Options = ParsedOptions> {
   /**
    * pipeline stages, e.g. if command='a b --foo|c', the pipeStages=[['a','b, '--foo'],'c']
    */
-  pipeStages: { prefix?: string; stages: string[][]; redirect?: string }
+  pipeStages: {
+    prefix?: string
+    stages: string[][]
+    redirect?: string
+    redirector?: '>' | '>>' | '2>&1' | '>&' | '>>&'
+  }
 
   /**
    * the dash options parsed out in a way that pays attention to n-ary

packages/core/src/repl/pipe-stages.ts

@@ -25,25 +25,28 @@ import { CommandLine } from '../models/command'
  *
  */
 export function splitIntoPipeStages(command: string): CommandLine['pipeStages'] {
+  // This covers the standard bash convention of using -- to split the
+  // command line into a "prefix" part and a "rest" part.
   const dashDashPattern = /--\s/
-  const redirectPattern = /([^"'\\])>/
+
+  // This covers > and >>, but excludes '>' and ">" and \>.
+  // WARNING: this regexp uses negaive lookbehind. Firefox only got
+  // support for this in Firefox version 78 (released July 30 2020).
+  const redirectPattern = /\d?(?<!["'\\])((>>?)&?\d?)/
 
   const dashDashMatch = command.match(dashDashPattern)
   const pipeStartIdx = dashDashMatch ? dashDashMatch.index + '--'.length : undefined
   const prefix = !dashDashMatch ? '' : command.slice(0, dashDashMatch.index).trim()
 
   const redirectMatch = command.match(redirectPattern)
   const pipeEndIdx = redirectMatch ? redirectMatch.index : undefined
-  const redirect = !redirectMatch
-    ? ''
-    : command
-        .slice(pipeEndIdx)
-        .replace(/^\s*>/, '')
-        .trim()
+  const redirect = !redirectMatch ? '' : command.slice(redirectMatch.index + redirectMatch[0].length).trim()
+
+  const redirector = !redirectMatch ? undefined : (redirectMatch[0] as CommandLine['pipeStages']['redirector'])
 
   const stages = split(command, false, undefined, '|', pipeStartIdx, pipeEndIdx).map(_ =>
     split(_, false).map(_ => _.replace(/\\\s/g, ''))
   )
 
-  return { prefix, stages, redirect }
+  return { prefix, stages, redirect, redirector }
 }

plugins/plugin-client-common/src/components/Views/Terminal/Block/FancyPipeline.tsx

@@ -17,7 +17,7 @@
 import React from 'react'
 import { Arguments } from '@kui-shell/core'
 
-type Props = Pick<Arguments['pipeStages'], 'prefix' | 'stages' | 'redirect'> & Pick<Arguments, 'REPL'>
+type Props = Pick<Arguments['pipeStages'], 'prefix' | 'stages' | 'redirect' | 'redirector'> & Pick<Arguments, 'REPL'>
 
 export default class FancyPipeline extends React.PureComponent<Props> {
   private linebreak() {
@@ -33,7 +33,7 @@ export default class FancyPipeline extends React.PureComponent<Props> {
    * e.g. somePrefix -- foo | bar > baz
    */
   public render() {
-    const { prefix, stages, redirect, REPL } = this.props
+    const { prefix, stages, redirect, redirector, REPL } = this.props
 
     return (
       <span className="repl-input-element flex-fill">
@@ -69,7 +69,7 @@ export default class FancyPipeline extends React.PureComponent<Props> {
         {redirect && (
           <React.Fragment>
             {this.linebreak()}
-            {this.pipe('>')}
+            {this.pipe(redirector)}
             <span className="clickable" onClick={() => REPL.pexec(`ls ${redirect}`)}>
               {redirect}
             </span>