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JSON command line

Batch Convert Files from the Windows Command Line

Convert supported files from PowerShell and return a clear result that another script can read.

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Short answer

Open PowerShell in the standalone installation folder and convert one copied test file before you automate a folder. These steps use the standalone installation's accessible cli folder.

This guide covers Just Converter. Check requirements and download options before you begin.

On this page

When to use it | What you need | Build the command | Command shape | Troubleshoot | Final checks

When to use this method

The command-line interface, or CLI, is useful for repeatable local jobs and scripts. It does not turn unsupported input into a valid conversion and it should not expose passwords or private contents in logs.

What you need before using the command line

  • The standalone installation of Just Converter.
  • One copied test file and one writable output folder.
  • PowerShell, which is included with Windows.

The Microsoft Store package does not register a PowerShell command alias. This path-based workflow is for the standalone installation, where JustConverter.Cli.exe is in the cli folder.

Build a reliable command

  1. Open PowerShell in the installation folder

    In File Explorer, open the installation folder. Click its address bar, type powershell, and press Enter.

    You should see: a PowerShell window whose prompt ends with the installation folder.

  2. Check the command-line tool

    Run .\cli\JustConverter.Cli.exe --help.

    You should see: the convert command and its available options.

  3. Convert one copied test file

    Put a copied photo.png in a folder named Conversion test under your Pictures folder. The quoted paths below allow spaces. Adjust them if your Pictures folder is elsewhere.

    $inputFile = "$env:USERPROFILE\Pictures\Conversion test\photo.png"
$outputFolder = "$env:USERPROFILE\Pictures\Converted test"
.\cli\JustConverter.Cli.exe convert `
  --input $inputFile `
  --format jpg `
  --output $outputFolder `
  --collision rename

    Copy the whole block. The backtick at the end of each command line continues it on the next line; do not add spaces after it.

    You should see: a separate JPG in Converted test and a success result. Open the JPG before converting more files.

  4. Add recursion deliberately

    Use recursive discovery only when nested folders are intended.

    You should see: nested files in the result only when you supplied --recursive.

  5. Choose collision behavior

    Select rename, overwrite or skip explicitly instead of relying on an assumption.

    You should see: each existing name handled by the option you chose.

  6. Read JSON and exit codes

    Add --json when a script needs the result. Capture the exit code immediately, then inspect the per-file status and output paths:

    $inputFile = "$env:USERPROFILE\Pictures\Conversion test\photo.png"
$outputFolder = "$env:USERPROFILE\Pictures\Converted test"
$json = .\cli\JustConverter.Cli.exe convert `
  --input $inputFile `
  --format jpg `
  --output $outputFolder `
  --collision rename `
  --json
$exitCode = $LASTEXITCODE
$result = $json | ConvertFrom-Json
$exitCode
$result.files | Select-Object inputDisplayName, status, outputs, safeErrorCode

    You should see: one result entry per input. A startup or validation error can return an exit code without JSON, so check the error message if parsing has nothing to read.

    PowerShell showing a successful Just Converter JSON result with one input file and one output file.
    Check the state and per-file status, then open the output path shown in the result.
Command-line behaviorSupported inputs, machine-readable results and the final output check.
How it works
The command accepts input paths, format, output, profile, collision mode, recursion and JSON output through a documented contract. It returns structured JSON and an exit code that a script can read.
Important limit
Shell success is not a fidelity check. A script must inspect the returned status and validate the created files.

Documented command shape

Replace each value in angle brackets, such as <path>, with the path, format, or other value your job needs.

Scroll the table horizontally on a narrow screen.

Part Example
Command .\cli\JustConverter.Cli.exe convert --input <path>... --format <format>
Optional output --output <directory> --profile <id>
Collision and discovery --collision rename|overwrite|skip --recursive
Machine-readable status --json
Exit codes 0 success; 1 usage or validation error; 2 no successful outputs; 3 partial success; 4 canceled; 5 required engine missing; 6 security or resource limit; 7 input/output or system failure

If the command fails or returns mixed results

Read the JSON result for each file before looking only at the final exit code. Check quoted paths, the chosen operation, output permissions, collision behavior and optional components. Read $LASTEXITCODE immediately after the converter command, before another native command changes it. Do not treat a created file as proof of success until the result status and the file itself both pass inspection.

Watch for

Command-line automation mistakes

  • Logging passwords or private file contents
  • Using overwrite before checking the destination folder
  • Ignoring nonzero exit codes or per-file status
Verify the result

Command checkpoint

  • Before adding recursion or a scheduler, test one representative file. It should return exit code 0, include a successful JSON entry and create an output that opens correctly.
  • The returned output paths and skipped-file messages match the chosen collision policy; JSON does not provide a separate log of every rename or overwrite.
  • If the exit code, JSON status or opened file disagrees, stop and inspect the command and per-file result.
Step by step

Just Converter

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