Batch + powershell script renamer wrong directory error - batch-file

Question

Code below works when I am in a directory:
gci | % {rni $_.Name ($_.Name -replace '120', '121')}
How do I create a batch file with powershell code that will work in every directory without errors. I just want to start file.bat that will rename all files in every folder where file.bat is located?
powershell -C "gci | % {rni $_.Name ($_.Name -replace '120', '121')}"
That doesn't work, here is error:
Expressions are only permitted as the first element of a pipeline.
At line:1 char:52 + gci | {rni $_.Name ($_.Name -replace '501', '121')} <<<<

Answer 1

Comedy answer:
echo Hi
is a batch file that will "work in any directory without errors", which is literally what you asked for.
Half serious answer, here is a batch file which will do the equivalent renaming of 120 to 121 in files in the current folder, what your PowerShell does, which is plausibly what you ask for:
#echo off
setlocal ENABLEDELAYEDEXPANSION
for %%f in (*120*) do (
set _f=%%f
ren "%%f" "!_f:120=121!"
)
Although even though you asked about Batch files and tagged the question about batch files, I suspect that's not what you want. Maybe you mean "how can I specify the directory for it to run against?" Then maybe this:
powershell -C "gci '%1' | % {rni $_.Name ($_.Name -replace '120', '121')}"
Where you save this as a batch file to run from a command prompt, %1 is the parameter you give to the batch file which is embedded in the PowerShell code, quoted as the input to gci. Then you could run myscript.bat "c:\data files" which would launch PowerShell and rename files in "c:\data files\".
Or maybe if you are asking more about the "with no errors" part from your title, then you need to accept that you might not have permission to list folder contents, or permission to rename files, or renaming files might lead to clashing names, in that case what you need is to add
`-ErrorAction -Ignore`
to gci and to rni, which will make them "run without errors", in a sense.
Serious answer: % is a special character in batch files, you need to escape it by writing it twice.
powershell -C "gci | %% {rni $_.Name ($_.Name -replace '120', '121')}"
Otherwise it gets swallowed and you get the error "Expressions are only allowed as the first element of a pipeline."
NB. You are trying to rename every file in the folder, regardless of whether it has 120 in the name or not, this is horrible. Follow Nikhil Gupta's suggestions on how to avoid doing that.

Answer 2

You could have been a little more specific. I'm making assumptions now to try and solve your issue -
You want to rename all the files with 120 in the name to now have 121.
You want to do it in a specific directory but want to run the script from any location on the cmd.
The current script would run in any directory, get all the child items in that directory and replace 120 with 121. It wouldn't work if the name doesn't have 120.
Based on this I suggest 2 modifications -
Add a filter while gci to get only the items with 120 in the name.
Add a first line to go to the directory you need the script to run under.
Here is the sample code -
Set-location <dir>
gci -Filter "*120*" | % {rni $_.Name ($_.Name -replace '120', '121')}