How many digits in git SHA to identify a commit?

 

How many digits in a git SHA makes it to identify the commit? 

7 digits are the Git default for a short SHA, so that's fine for most projects. 

For  ~30k commits, 8 or 10 digits should be perfectly fine.

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To get the last abbreviated one:

git rev-parse --short HEAD

To list the log entries with abbreviated ones:

git log --abbrev-commit