Recently my HTPC, Windows Media Center (WMC) running under Windows 7, started to exhibit an odd issue. One or two of the recordings couldn’t be deleted from within WMC. So I tried falling back to closing down WMC and deleting the files from the Recorded TV directory, only to receive an “Access Denied” error message. Ok, let’s run a shell (cmd) as the administrator user change to the Recorded TV directory and use del to delete the files. Still I got the “Access Denied” error message.

Looking at the files properties showed even more odd results, they weren’t owned by anyone. When I tried to change the owner to the administrator account I go the same error message. This was the point that I decided to fall back to basics, if the file system is behaving oddly then check the disk, so I ran

chkdsk c: /R

It replied that it couldn’t check it now but would I like to check it on the next restart, which of course I said yes to and then immediately restarted the machine. 20 minutes later, after a full disk check, windows reappeared and I could delete the files. My current assumption is that windows had lost some of the ntfs details for the files and that the chkdsk reset them.

I have just started using PowerShell instead of CMD and I can say that it is a big improvement. The first thing I wanted to do though was to edit my profile so that I could tailor it to me.

First I listed my initial requirements

• Don’t put anything in the prompt except >
• vi, vim, gvim should all launch gvim for editing files
• gimp should launch gimp for editing image files
• <CTRL>+D should close powershell down

First I discovered that I would have to change my execution policy for PowerShell. This was a simple case of launching PowerShell as an administrator and entering

Set-ExecutionPolicy RemoteSigned

This lets PowerShell run local scripts but requires remote scripts to have been signed. After doing that I closed down the Administrator PowerShell and opened one as my standard user.

To edit my profile I initially used the command:

notepad $profile

and entered the following

# Functions

# prompt function, redefines what prompt is displayed
function prompt
---
"> "

After closing PowerShell and reopening it I now had a simple ‘>’ as the prompt.

The next step was to put in the aliases for vi, vim, gvim and gimp. So I edited the profile again and entered

# Assign vi, vim, gvim to gvim
Set-Alias vim 'C:\Program Files (x86)\Vim\vim73\gvim.exe'
Set-Alias gvim vim
Set-Alias vi vim

# Assign gimp to gimp
Set-Alias gimp 'C:\Program Files (x86)\GIMP-2.0\bin\gimp-2.6.exe'

After restarting PowerShell again I could now edit my profile by using

vim $profile

Now that I was using vim to edit my profile I could use <CTRL>+V to insert special characters. Which would let me put a <CTRL>+D (^D) in my profile, specifically as an alias, though I would still have to press <CTRL>+D followed by <RETURN>. Initially I tried

Set-Alias ^D exit

But that didn’t work. Ironically it wasn’t the <CTRL>+D character causing problems, instead it was the use of exit in an alias. The solution is to wrap exit in a function and call the function from the alias.

# ex function, required to use exit in aliases
function ex
---
    exit

# Aliases

# Assign CTRL+D to exit
Set-Alias ^D ex

That so far is my standard PowerShell profile. Here it is in one chunk incase you want to cut and paste (remembering to replace ^D with a proper <CTRL>+D character).

# Functions

# prompt function, redefines what prompt is displayed
function prompt
---
"> "

# ex function, required to use exit in aliases
function ex
---
exit

# Aliases

# Assign CTRL+D to exit
Set-Alias ^D ex

# Assign vi, vim, gvim to gvim
Set-Alias vim 'C:\Program Files (x86)\Vim\vim73\gvim.exe'
Set-Alias gvim vim
Set-Alias vi vim

# Assign gimp to gimp
Set-Alias gimp 'C:\Program Files (x86)\GIMP-2.0\bin\gimp-2.6.exe'