The goal of this script [right now] is to tell you how to "undo" a command. for example undo cd path/to/somewhere would result in "cd -" which will go back to the previous directory, and for example if you do mv path/to/a path/to/b this would produce "mv path/to/b path/to/a"

undo

#!/usr/bin/php
<?php
if (!isset($argv[1])){ 
   die('Usage: undo <command-to-try-and-undo>'."\n");
}
 
$OLDPWD = `echo "\$OLDPWD"`;
 
$allargs = $argv;
array_shift($allargs);
 
$undo = new Undo($allargs);
$reverse_cmd = $undo->getReverseCommand();
if ($reverse_cmd){
   echo $reverse_cmd;
}else{
   echo "'".$allargs[0].'\' not yet supported. Supported reversable commands are: '.Undo::GetSupportedCommands();
}
die("\n");
 
class Undo{
   public static $quick_reverse = array('cd'=>'cd -');
   public static $twolevel_reverse = array('git checkout'=>'git checkout -');
   public static $special_reverse = array('mv'=>'mv {2} {1}');
 
   public static function GetSupportedCommands(){ return implode(array_keys(self::$quick_reverse),','); }
   //------------------------------------------------------------------------------------------
   
   private $cmd_str = '';
   private $cmd_ary = array();
   public function __construct($cmd_ary){
       $this->cmd_str = implode($cmd_ary, ' ');
       $this->cmd_ary = $cmd_ary;
   }
 
    
   public function getReverseCommand($cmd = null, $ary = null){
       if ($cmd === null){ $cmd = $this->cmd_str; }
       if ($ary === null){ $ary = $this->cmd_ary; }
 
       $cmd = strtolower($cmd);
 
 
       if (isset(self::$quick_reverse[$ary[0]])){
          return self::$quick_reverse[$ary[0]];
       }
       if (isset($ary[1])){
          if (isset(self::$twolevel_reverse[$ary[0].' '.$ary[1]])){
             return self::$twolevel_reverse[$ary[0].' '.$ary[1]];
          }
       }
       foreach(self::$special_reverse as $scmd => $reversal_cmd){
           if ($scmd === $ary[0]){
                 $newcmd = '';
                 $newcmd = $reversal_cmd;
                 foreach($ary as $i => $arg){
                     $newcmd = str_replace('{'.$i.'}', $ary[$i], $newcmd);
                 }
                 return $newcmd;
           }
       }
       return false;
   }
}