rename this to .git/hooks/pre-commit inside your git repo to prevent accidental commits that you tagged as DNC (do-not-commit)

DNC_pre-commit.png

pre-commit.sh

#!/bin/sh
#
# https://twitter.com/pestophagous/status/501460327515815936

if git-rev-parse --verify HEAD >/dev/null 2>&1
then
    against=HEAD
else
    # Initial commit: diff against an empty tree object
    against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
fi

# DNC stands for 'do not commit'
MARKER_STRING_TO_PREVENT_A_COMMIT="DNC DNC DNC"

COUNT_BAD_DISALLOWED_LINES=`git diff --cached $against | grep "${MARKER_STRING_TO_PREVENT_A_COMMIT}" | wc -l`

if [ "$COUNT_BAD_DISALLOWED_LINES" -eq "0" ]
then
    # don't do anything. we are happy so far.
    true
else
    echo "custom pre-commit script is BLOCKING this commit!  You have \"$MARKER_STRING_TO_PREVENT_A_COMMIT\" (do not commit) in your source file!"
    exit 1
fi