Simple script to list grub os's and boot one.

Post

Posted
Rating:
#1 (In Topic #882)
BruceSteers
Guru
BruceSteers is in the usergroup ‘Guru’
here is a simple script the utilizes the grub-reboot command to select what os to boot into the next boot only. (useful if you have a few test OS's to choose from)

It reads grub.cfg and gets the main entries then lists them.
Double click an os to have it as the next boot os. then after rebooting out of that os it reverts to the default.

Note.
/etc/default/grub file MUST have the default line set to "saved" like this…

GRUB_DEFAULT=saved
if you changed the default to saved from something else then you have to run update-grub

then save this script somewhere, set it's exe flag and launch it.

Code (gambas)

  1. #!/usr/bin/env gbs3
  2. ' Gambas script file
  3.  
  4. Use "gb.gui"
  5. Use "gb.desktop"
  6.  
  10.  
  11. Private iTextLen As Integer
  12.  
  13. Public Sub Main()
  14.  
  15.   Dim sRet As String, aLines As String[]
  16.  
  17.   With fForm = New Form
  18.     .Spacing = True
  19.     .Margin = True
  20.     .Title = "Select OS to boot next boot"
  21.     .Arrangement = Arrange.Vertical
  22.     .Foreground = Color.Magenta
  23.    End With
  24.  
  25.   lList = New ListBox(fForm) As "List"
  26.   lList.Font = Font["Ubuntu,16"]
  27.   lList.Expand = True
  28.  
  29.   aLines = GetMainEntries()
  30.  
  31.   lList.List = aLines.Copy()
  32.   lList.Background = Color.SetAlpha(Color.Cyan, 220)
  33.   fForm.Width = iTextLen + (Desktop.Scale * 3)
  34.   fForm.Height = (lList.List.Count + 4) * lList.Font.Height
  35.  
  36.   With cBox = New CheckBox(fForm)
  37.   .Text = "Reboot after setting. (no confirmation)"
  39.  
  40.   fForm.Show
  41.  
  43.  
  44. Public Sub List_Activate()
  45.  
  46.   Desktop.RunAsRoot("grub-reboot \"" & Last.Text & "\"", True)
  47.   fForm.Hide()
  48.   If Not cBox.Value Then
  49.     If Message.Question("Next reboot set to...\n " & Last.Text, "Reboot now", "Reboot Later") <> 1 Then Return
  51.   Shell "reboot"
  52.   fForm.Close()
  53.  
  55.  
  56. Public Sub GetMainEntries() As String[]
  57.  
  58.   Dim sEntries As New String[]
  59.   Dim sLines As String[] = Split(File.Load("/boot/grub/grub.cfg"), "\n", Null, True)
  60.  
  61.   Dim bInSub As Boolean
  62.   Dim iDepth As Integer
  63.  
  64.   For Each s As String In sLines
  65.  
  66.     If bInSub Then
  67.       If LTrim(s) Begins "menuentry " Then
  68.         Inc iDepth
  69.       Else If Trim(s) = "}" Then
  70.         Dec iDepth
  71.         If iDepth < 0 Then bInsub = False
  72.  
  73.       Endif
  74.     Else
  75.       If LTrim(s) Begins "menuentry " Then
  76.         sEntries.Add(Split(s, If(InStr(s, "'"), "'", "\""))[1])
  77.         iTextLen = Max(iTextLen, lList.Font.TextWidth(sEntries.Last))
  78.       Else If LTrim(s) Begins "submenu " Then
  79.         Idepth = 0
  80.         bInSub = True
  81.       Endif
  82.  
  83.     Endif
  84.  
  85.   Next
  86.  
  87.   Return sEntries
  88.  
  90.  
Online now: No Back to the top
1 guest and 0 members have just viewed this.