Windows batch file net command not setting errorlevel

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I'm trying to determine if a script runs with admin authorities on Win7, but errorlevel doesn't seem to get set consistently after executing a "net" command...

This is (simplified) my code:

net session >null 2>$1
if %errorLevel% == 0 (
  echo This seems to be mighty ADMIN...
) else (
  echo Poor sod... no Admin, no glory - errorLevel: %errorLevel%
)

@SETLOCAL
@set TSTHOME=%~dp0
@set TSTNAME=%~n0

set SAL=NO
set SCL=NO
:VAL_PARM
  if .%1 == . @goto :VAL_PARM_END
  if /i %1 == SAL (
    net session >null 2>$1
    if %errorLevel% == 0 (
      set SAL=YES
    ) else (
      echo Option "SAL" requires Administrator priviliges (run "as Admin" or from an elevated command prompt)
      goto :EOF
    )
  ) else (
    if /i %1 == SCL (
      set SCL=YES
    ) else (
      echo off
      echo Invalid argument "%1"; correct syntax: %TSTNAME% [SAL] [SCL]
      echo                        where:   SAL: save agent  logs of each command
      echo                                 SCL: save client logs of each command
      echo                        NOTE: "SAL" requires "Administrator" privileges
      goto :EOF
    )
  )
  shift
  goto :VAL_PARM
:VAL_PARM_END

But when I run this from a regular command prompt, this is the output:

C:\MyDir>isAdmin sal

C:\MyDir>net session 1>null 2>$1

C:\MyDir>if 2 == 0 (echo This seems to be mighty ADMIN... ) else (echo Poor sod... no Admin, no glory - errorLevel: 2 )
Poor sod... no Admin, no glory - errorLevel: 2

C:MyDir>set SAL=NO

C:\MyDir>set SCL=NO

C:\MyDir>if .sal == .

C:\MyDir>if /I sal == SAL (
net session 1>null 2>$1
if 0 == 0 (set SAL=YES )
else (echo Option "SAL" requires Administrator priviliges (run "as Admin" or from an elevated command prompt )
goto :EOF )

Why for heaven's sake is the second "net session" not setting errorLevel???

1

There are 1 answers

2
Joey On

Don't compare errorlevels like that, as the variable will be expanded before the if block even executes and thus retains its value from before the block. Use the following instead:

if not errorlevel 1 ...

or use delayed expansion. You can read up about that in help set.