Set-PSBreakpoint

Sets a breakpoint on a line, command, or variable.

Syntax

Set-PSBreakpoint
   [-Action <ScriptBlock>]
   [[-Column] <Int32>]
   [-Line] <Int32[]>
   [-Script] <String[]>
   [<CommonParameters>]
Set-PSBreakpoint
   [-Action <ScriptBlock>]
   -Command <String[]>
   [[-Script] <String[]>]
   [<CommonParameters>]
Set-PSBreakpoint
   [-Action <ScriptBlock>]
   [[-Script] <String[]>]
   -Variable <String[]>
   [-Mode <VariableAccessMode>]
   [<CommonParameters>]

Description

The Set-PSBreakpoint cmdlet sets a breakpoint in a script or in any command run in the current session. You can use Set-PSBreakpoint to set a breakpoint before executing a script or running a command, or during debugging, when stopped at another breakpoint.

Set-PSBreakpoint cannot set a breakpoint on a remote computer. To debug a script on a remote computer, copy the script to the local computer and then debug it locally.

Each Set-PSBreakpoint command creates one of the following three types of breakpoints:

  • Line breakpoint - Sets breakpoints at particular line and column coordinates.
  • Command breakpoint - Sets breakpoints on commands and functions.
  • Variable breakpoint - Sets breakpoints on variables.

You can set a breakpoint on multiple lines, commands, or variables in a single Set-PSBreakpoint command, but each Set-PSBreakpoint command sets only one type of breakpoint.

At a breakpoint, PowerShell temporarily stops executing and gives control to the debugger. The command prompt changes to DBG\>, and a set of debugger commands become available for use. However, you can use the Action parameter to specify an alternate response, such as conditions for the breakpoint or instructions to perform additional tasks such as logging or diagnostics.

The Set-PSBreakpoint cmdlet is one of several cmdlets designed for debugging PowerShell scripts. For more information about the PowerShell debugger, see about_Debuggers.

Examples

Example 1: Set a breakpoint on a line

This example sets a breakpoint at line 5 in the Sample.ps1 script. When the script runs, execution stops immediately before line 5 would execute.

Set-PSBreakpoint -Script "sample.ps1" -Line 5

Column     : 0
Line       : 5
Action     :
Enabled    : True
HitCount   : 0
Id         : 0
Script     : C:\ps-test\sample.ps1
ScriptName : C:\ps-test\sample.ps1

When you set a new breakpoint by line number, the Set-PSBreakpoint cmdlet generates a line breakpoint object (System.Management.Automation.LineBreakpoint) that includes the breakpoint ID and hit count.

Example 2: Set a breakpoint on a function

This example creates a command breakpoint on the Increment function in the Sample.ps1 cmdlet. The script stops executing immediately before each call to the specified function.

Set-PSBreakpoint -Command "Increment" -Script "sample.ps1"

Command    : Increment
Action     :
Enabled    : True
HitCount   : 0
Id         : 1
Script     : C:\ps-test\sample.ps1
ScriptName : C:\ps-test\sample.ps1

The result is a command breakpoint object. Before the script runs, the value of the HitCount property is 0.

Example 3: Set a breakpoint on a variable

This example sets a breakpoint on the Server variable in the Sample.ps1 script. It uses the Mode parameter with a value of ReadWrite to stop execution when the value of the variable is read and just before the value changes.

Set-PSBreakpoint -Script "sample.ps1" -Variable "Server" -Mode ReadWrite

Example 4: Set a breakpoint on every command that begins with specified text

This example sets a breakpoint on every command in the Sample.ps1 script that begins with "write", such as Write-Host.

Set-PSBreakpoint -Script Sample.ps1 -Command "write*"

Example 5: Set a breakpoint depending on the value of a variable

This example stops execution at the DiskTest function in the Test.ps1 script only when the value of the $Disk variable is greater than 2.

Set-PSBreakpoint -Script "test.ps1" -Command "DiskTest" -Action { if ($Disk -gt 2) { break } }

The value of the Action is a script block that tests the value of the $Disk variable in the function.

The action uses the break keyword to stop execution if the condition is met. The alternative (and the default) is Continue.

Example 6: Set a breakpoint on a function

This example sets a breakpoint on the CheckLog function. Because the command does not specify a script, the breakpoint is set on anything that runs in the current session. The debugger breaks when the function is called, not when it is declared.

PS> Set-PSBreakpoint -Command "checklog"
Id       : 0
Command  : checklog
Enabled  : True
HitCount : 0
Action   :

function CheckLog {
>> get-eventlog -log Application |
>> where {($_.source -like "TestApp") -and ($_.Message -like "*failed*")}
>>}
>>
PS> Checklog
DEBUG: Hit breakpoint(s)
DEBUG:  Function breakpoint on 'prompt:Checklog'

Example 7: Set breakpoints on multiple lines

This example sets three line breakpoints in the Sample.ps1 script. It sets one breakpoint at column 2 on each of the lines specified in the script. The action specified in the Action parameter applies to all breakpoints.

PS C:\> Set-PSBreakpoint -Script "sample.ps1" -Line 1, 14, 19 -Column 2 -Action {&(log.ps1)}

Column     : 2
Line       : 1
Action     :
Enabled    : True
HitCount   : 0
Id         : 6
Script     : C:\ps-test\sample.ps1
ScriptName : C:\ps-test\sample.ps1


Column     : 2
Line       : 14
Action     :
Enabled    : True
HitCount   : 0
Id         : 7
Script     : C:\ps-test\sample.ps1
ScriptName : C:\ps-test\sample.ps1


Column     : 2
Line       : 19
Action     :
Enabled    : True
HitCount   : 0
Id         : 8
Script     : C:\ps-test\sample.ps1
ScriptName : C:\ps-test\sample.ps1

Parameters

-Action

Specifies commands that run at each breakpoint instead of breaking. Enter a script block that contains the commands. You can use this parameter to set conditional breakpoints or to perform other tasks, such as testing or logging.

If this parameter is omitted, or no action is specified, execution stops at the breakpoint, and the debugger starts.

When the Action parameter is used, the Action script block runs at each breakpoint. Execution does not stop unless the script block includes the Break keyword. If you use the Continue keyword in the script block, execution resumes until the next breakpoint.

For more information, see about_Script_Blocks, about_Break, and about_Continue.

Type:ScriptBlock
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False
-Column

Specifies the column number of the column in the script file on which execution stops. Enter only one column number. The default is column 1.

The Column value is used with the value of the Line parameter to specify the breakpoint. If the Line parameter specifies multiple lines, the Column parameter sets a breakpoint at the specified column on each of the specified lines. PowerShell stops executing before the statement or expression that includes the character at the specified line and column position.

Columns are counted from the top left margin beginning with column number 1 (not 0). If you specify a column that does not exist in the script, an error is not declared, but the breakpoint is never executed.

Type:Int32
Position:2
Default value:1
Accept pipeline input:False
Accept wildcard characters:False
-Command

Sets a command breakpoint. Enter cmdlet names, such as Get-Process, or function names. Wildcards are permitted.

Execution stops just before each instance of each command is executed. If the command is a function, execution stops each time the function is called and at each BEGIN, PROCESS, and END section.

Type:String[]
Aliases:C
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:True
-Line

Sets a line breakpoint in a script. Enter one or more line numbers, separated by commas. PowerShell stops immediately before executing the statement that begins on each of the specified lines.

Lines are counted from the top left margin of the script file beginning with line number 1 (not 0). If you specify a blank line, execution stops before the next non-blank line. If the line is out of range, the breakpoint is never hit.

Type:Int32[]
Position:1
Default value:None
Accept pipeline input:False
Accept wildcard characters:False
-Mode

Specifies the mode of access that triggers variable breakpoints. The default is Write.

This parameter is valid only when the Variable parameter is used in the command. The mode applies to all breakpoints set in the command. The acceptable values for this parameter are:

  • Write - Stops execution immediately before a new value is written to the variable.
  • Read - Stops execution when the variable is read, that is, when its value is accessed, either to be assigned, displayed, or used. In read mode, execution does not stop when the value of the variable changes.
  • ReadWrite - Stops execution when the variable is read or written.
Type:VariableAccessMode
Accepted values:Read, Write, ReadWrite
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False
-Script

Specifies an array of script files that this cmdlet sets a breakpoint in. Enter the paths and file names of one or more script files. If the files are in the current directory, you can omit the path. Wildcards are permitted.

By default, variable breakpoints and command breakpoints are set on any command that runs in the current session. This parameter is required only when setting a line breakpoint.

Type:String[]
Position:0
Default value:None
Accept pipeline input:False
Accept wildcard characters:False
-Variable

Specifies an array of variables that this cmdlet sets breakpoints on. Enter a comma-separated list of variables without dollar signs ($).

Use the Mode parameter to determine the mode of access that triggers the breakpoints. The default mode, Write, stops execution just before a new value is written to the variable.

Type:String[]
Aliases:V
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False

Inputs

None

You cannot pipe input to Set-PSBreakpoint.

Outputs

Breakpoint object (System.Management.Automation.LineBreakpoint, System.Management.Automation.VariableBreakpoint, System.Management.Automation.CommandBreakpoint)

Set-PSBreakpoint returns an object that represents each breakpoint that it sets.

Notes

  • Set-PSBreakpoint cannot set a breakpoint on a remote computer. To debug a script on a remote computer, copy the script to the local computer and then debug it locally.
  • When you set a breakpoint on more than one line, command, or variable, Set-PSBreakpoint generates a breakpoint object for each entry.
  • When setting a breakpoint on a function or variable at the command prompt, you can set the breakpoint before or after you create the function or variable.