When a program goes through the motions of making changes to data but doesn't what do you call this?

In my program I need a 'preview' mode where it doesn't make a开发者_C百科ny changes to the data, there's a common name for this that I've seen in other apps but I can't put my finger on it. Any ideas?

Thanks

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• "What If" (-whatif in powershell)
• Scenario (most accounting apps, business apps)
• Test/Demo/Preview (in most general apps)
• Model (in engineering and architectural apps)
• Modify/Modifications (in most office apps, but as part of the work flow, i.e. "Show Modifications")
• Uncomitted (in most operational systems/apps, i.e. "Show uncommitted changes" usually used in a workflow)

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I think you've hit the nail on the head - you have "Print Preview" in most word processors. "Preview your changes" is pretty common terminology.

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Subversion uses the term "dry run" to describe a merge (i.e. applying a patch from a branch) that doesn't write any changes to local files. This is useful if you want to check whether a given merge will conflict without actually performing the merge.

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In the context of data bases and source control systems this is called a "transaction". The operation of a transaction is not final until it is complete. In case the operation stops in the middle of the transaction, the entire operation can be withdrawn with no effects of the data.

This term doesn't usually apply to GUI application which present "previews" so it's probably not what you're looking for.

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Many command line tools have a mode like this, and they usually call it a "dry run". In Unix tools it's often enabled by the -n flag. For example, make -n will show you what commands make would execute without actually executing them.