Debugging PowerShell Scripts

function_example.ps1

1 <# 2 3 .SYNOPSIS 4 This material is used in Prakashan Korambath's PowerShell tutorial to demostrate function call 5 6 .EXAMPLE 7 8 PS > function_example <value> 9 10 #> 11 12 param( 13 [Parameter(Mandatory=$True)] 14 15 [double] $Fahrenheit 16 ) 17 18 ## Convert Fahrenheit to Celsius 19 function ConvertFToC([double] $fahrenheit) 20 { 21 $celsius = ($fahrenheit - 32)/1.8 22 $celsius 23 } 24 25 $celsius = ConvertFToC $fahrenheit 26 Write-Host "Temperature in Celsisus : = " $celsius.ToString("#.##") "degree Celsius"

# Clear all existing break pointsGet-PSBreakpoint | Remove-PSBreakpoint
# Set a breakpoint on line 22Set-PSBreakpoint -Line 22 -Script .\function_example.ps1 ID Script Line Command Variable Action -- ------ ---- ------- -------- ------ 4 function_example.ps1 22
# Run the script function_example.ps1 and input a value of 80 when asked and press return.\function_example.ps1cmdlet function_example.ps1 at command pipeline position 1Supply values for the following parameters:Fahrenheit: 80
# You will get an output like thisHit Line breakpoint on 'C:\Users\ppk\windows-pshell\function_example.ps1:22'At C:\Users\ppk\windows-pshell\function_example.ps1:22 char:5+ $celsius+ ~~~~~~~~
# Type ? or h then it will print you all the debugging commands[DBG]: PS C:\Users\ppk\windows-pshell>> ? s, stepInto Single step (step into functions, scripts, etc.) v, stepOver Step to next statement (step over functions, scripts, etc.) o, stepOut Step out of the current function, script, etc. c, continue Continue operation q, quit Stop operation and exit the debugger d, detach Continue operation and detach the debugger. k, Get-PSCallStack Display call stack l, list List source code for the current script. Use "list" to start from the current line, "list <m>" to start from line <m>, and "list <m> <n>" to list <n> lines starting from line <m> <enter> Repeat last command if it was stepInto, stepOver or list ?, h displays this help message.For instructions about how to customize your debugger prompt, type "help about_prompt".
# If you type the variables you want it will print the current contents
[DBG]: PS C:\Users\ppk\windows-pshell>> $fahrenheit80[DBG]: PS C:\Users\ppk\windows-pshell>> $celsius26.6666666666667
# if you type "s" couple of times it will step to next line
[DBG]: PS C:\Users\ppk\windows-pshell>> sAt C:\Users\ppk\windows-pshell\function_example.ps1:23 char:1+ }+ ~[DBG]: PS C:\Users\ppk\windows-pshell>> sAt C:\Users\ppk\windows-pshell\function_example.ps1:26 char:1+ Write-Host "Temperature in Celsisus : = " $celsius.ToString("#.##") " ...+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~[DBG]: PS C:\Users\ppk\windows-pshell>> sTemperature in Celsisus : = 26.67 degree Celsius
# Additionally one can also set breakpoint for a variable
PS C:\Users\ppk\windows-pshell> Get-PSBreakpoint | Remove-PSBreakpointPS C:\Users\ppk\windows-pshell> Set-PSBreakpoint -Variable "celsius" -Mode write -Script .\function_example.ps1
ID Script Line Command Variable Action -- ------ ---- ------- -------- ------ 5 function_example.ps1 celsius
PS C:\Users\ppk\windows-pshell> .\function_example.ps1
cmdlet function_example.ps1 at command pipeline position 1Supply values for the following parameters:Fahrenheit: 80Hit Variable breakpoint on 'C:\Users\ppk\windows-pshell\function_example.ps1:$celsius' (Write access)
At C:\Users\ppk\windows-pshell\function_example.ps1:21 char:5+ $celsius = ($fahrenheit - 32)/1.8+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~[DBG]: PS C:\Users\ppk\windows-pshell>> $celsius26.6666666666667[DBG]: PS C:\Users\ppk\windows-pshell>> cHit Variable breakpoint on 'C:\Users\ppk\windows-pshell\function_example.ps1:$celsius' (Write access)
At C:\Users\ppk\windows-pshell\function_example.ps1:25 char:1+ $celsius = ConvertFToC $fahrenheit+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~[DBG]: PS C:\Users\ppk\windows-pshell>> qPS C:\Users\ppk\windows-pshell>