Added env command

README.md

@@ -28,7 +28,6 @@ A Bourne-compatible shell for ComputerCraft.
 ### TODO
 * Add test boolean operators (-a, -o)
 * Add case statement
-* Add /usr/bin/env equivalent
 
 ## License
 This project is licensed under the MIT license. You are free to modify and redistribute cash.lua as long as the copyright notice is preserved at the top of the script.

cash.lua

@@ -37,6 +37,7 @@ local running = true
 local shell_retval = 0
 local shell_title = nil
 local execCommand
+local shell_env = _ENV
 
 local function splitFile(filename)
     local file = io.open(filename, "r")
@@ -568,6 +569,14 @@ function multishell.getFocus()
     return 1
 end
 
+function shell.environment()
+    return shell_env
+end
+
+function shell.setEnvironment(e)
+    shell_env = e
+end
+
 local function expandVar(var)
     if string.sub(var, 1, 1) ~= "$" then return nil end
     if string.sub(var, 2, 2) == "{" then
@@ -827,7 +836,7 @@ local function execv(tokens)
         end
         local _old = vars._
         vars._ = path
-        run(setmetatable({shell = shell, multishell = multishell, package = pack, require = require}, {__index = _ENV}), path, table.unpack(tokens)) 
+        run(setmetatable({shell = shell, multishell = multishell, package = pack, require = require}, {__index = shell_env}), path, table.unpack(tokens)) 
         vars._ = _old
     end
     for k,v in pairs(tokens.vars) do _ENV[k] = oldenv[k] end

env.lua

@@ -0,0 +1,39 @@
+local args = {...}
+
+local env = setmetatable({}, {__index = _ENV})
+local path = shell.path()
+local unset = {}
+local cmd = {}
+local cmdargs = false
+local nextarg
+
+for k,v in ipairs(args) do
+    if nextarg then
+        if nextarg == 1 then path = v
+        elseif nextarg == 2 then table.insert(unset, v) end
+        nextarg = nil
+    elseif cmdargs then 
+        table.insert(cmd, v) 
+    else
+        if v == "-i" then setmetatable(env, {__index = _G})
+        elseif v == "-P" then nextarg = 1
+        elseif v == "-u" then nextarg = 2
+        elseif string.find(v, "=") then env[string.sub(v, 1, string.find(v, "=") - 1)] = string.sub(v, string.find(v, "=") + 1)
+        else table.insert(cmd, v); cmdargs = true end
+    end
+end
+
+if #unset > 0 then
+    local oldidx = getmetatable(env).__index
+    local u = {}
+    for k,v in ipairs(unset) do u[v] = true end
+    setmetatable(env, {__index = function(self, name) if u[name] then return nil else return oldidx[name] end end})
+end
+
+local oldPath = shell.path()
+local oldEnv = shell.environment()
+shell.setPath(path)
+shell.setEnvironment(env)
+shell.run(table.unpack(cmd))
+shell.setPath(oldPath)
+shell.setEnvironment(oldEnv)