bash -n is a basic but useful builtin syntax linter.

If you do not use the pre-commit Python command & hook manager (check it out, it's great!), you can define a git pre-commit hook "manually" by putting the following in a file at .git/hooks/pre-commit:

#!/bin/sh

# Redirect output to stderr:
exec 1>&2

echo "Executing bash native syntax linter on all modified .sh files:"
if ! git diff --cached --name-only --diff-filter=AM HEAD | grep '.sh$' | xargs -n 1 bash -n
then
  echo "Error : syntax issues were detected"
  exit 1
fi