backup-1

实战Linux编程的原代码,希望对学驱动的人能有所帮助

#!/bin/sh
# Try to create a symlink with backup where the destination file exists
# and the backup file name is a hard link to the destination file.
# Based on a problem report from Jamie Lokier.

if test "$VERBOSE" = yes; then
  set -x
  ln --version
fi

trap "rm -rf a b b~" 0 1 2 3 15

framework_failure=0
touch a b || framework_failure=1

if test $framework_failure = 1; then
  echo 'failure in testing framework'
  exit 1
fi

ln b b~ || fail=1
ln -f --b=simple a b || fail=1

exit $fail