PowerShell Script "&" "&&" "||" Operators

Question

I am new to PowerShell scripting. I have been given the task to understand what a PowerShell script is doing.

I am stuck at following line:

& $basePath\CPAU.exe -u $($sqlUser.UserName) -p $(ConvertTo-UnsecureString $sqlUser.Password) -ex "cmd /c (sqlcmd $($sqlArgs -join ' ') > $outputFile && echo TRUE > SUCCESS) || echo TRUE > FAILURE" -wait -nowarn -hide

It feels like the script is trying to execute some sort of sql command. However, I am not sure of starting "&" symbol.

Also, could CPAU.exe be an external in basepath? And what do -p, -u, and -ex enforce?

Next line:

if (!(Test-Path .\SUCCESS))
{
    #some more code
}

In above if statement, what does .\SUCCESS mean? Doesn't Test-Path operate on some sort of path to test whether it exists or not?

Thanks, could you write an answer explaining whole line? I still don't get what is "||" for and TRUE>FAILURE? — java_doctor_101
– java_doctor_101, Commented Nov 13, 2014 at 16:13
I'm not very good at powershell, just pointed out some things. The || is an or condition. — Cyclonecode
– Cyclonecode, Commented Nov 13, 2014 at 16:14

Ansgar Wiechers · Accepted Answer · 2014-11-13 16:24:38Z

5

& is the PowerShell call operator, which "runs a command, script, or script block". In your case it's running the external command CPAU.exe located in $basePath with the parameters -u, -p, -ex, -wait, -nowarn, and -hide. That command runs another command (the argument of the parameter -ex):

cmd /c (sqlcmd $($sqlArgs -join ' ') > $outputFile && echo TRUE > SUCCESS) || echo TRUE > FAILURE

The above uses cmd.exe (the Windows Command Prompt) to run sqlcmd $($sqlArgs -join ' '), redirect its output to the file $outputFile, and write "TRUE" to either the file SUCCESS if the command succeeded or to the file FAILURE otherwise.

|| and && are cmd operators for command chaining. || means "run the next command if the previous command failed". && means "run the next command if the previous command succeeded".

answered Nov 13, 2014 at 16:24

Ansgar Wiechers

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Micky Balladelli · Accepted Answer · 2014-11-13 16:33:11Z

& $basePath\CPAU.exe -u $($sqlUser.UserName) -p $(ConvertTo-UnsecureString $sqlUser.Password) -ex "cmd /c (sqlcmd $($sqlArgs -join ' ') > $outputFile && echo TRUE > SUCCESS) || echo TRUE > FAILURE" -wait -nowarn -hide

This is some Powershell code, calling the executable CPAU.exe stored in $basePath passing a username and password and making it execute some CMD code:

cmd /c (sqlcmd $($sqlArgs -join ' ') > $outputFile && echo TRUE > SUCCESS) || echo TRUE > FAILURE

The cmd executes a SQL command given some predefined $sqlArgs, joined by a space. The whole command is redirected to $outputFile which is also expected to be predefined.

If the output of the command AND the ability to Echo TRUE on the CMD console is true, a file called SUCCESS is created receiving the redirected output. Else, if something fails but the echo TRUE happens, a FAILURE file is created.

The whole thing waits for everything to be complete, gives no warning and ...hides....

Whoever wrote this, needs a vacation.

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