text: #!/bin/sh
  #
  # An example hook script to check the commit log message.
  # Called by "git commit" with one argument, the name of the file
  # that has the commit message.  The hook should exit with non-zero
  # status after issuing an appropriate message if it wants to stop the
  # commit.  The hook is allowed to edit the commit message file.
  #
  # To enable this hook, rename this file to "commit-msg".
  
  # Uncomment the below to add a Signed-off-by line to the message.
  # Doing this in a hook is a bad idea in general, but the prepare-commit-msg
  # hook is more suited to it.
  #
  # SOB=$(git var GIT_AUTHOR_IDENT | sed -n 's/^\(.*>\).*$/Signed-off-by: \1/p')
  # grep -qs "^$SOB" "$1" || echo "$SOB" >> "$1"
  
  # This example catches duplicate Signed-off-by lines.
  
  test "" = "$(grep '^Signed-off-by: ' "$1" |
  	 sort | uniq -c | sed -e '/^[ 	]*1[ 	]/d')" || {
  	echo >&2 Duplicate Signed-off-by lines.
  	exit 1
  }
  