empty-file

实战Linux编程的原代码,希望对学驱动的人能有所帮助

#!/bin/sh
# Make sure touch can set the mtime on an empty file.
# Volker Borchert reported that touch 3.16r (and presumably all before that)
# fails to work on SunOS 4.1.3 with `most of the recommended patches' when
# the empty file is on an NFS-mounted 4.2 volume.

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

DEFAULT_SLEEP_SECONDS=2
SLEEP_SECONDS=${SLEEP_SECONDS=$DEFAULT_SLEEP_SECONDS}

fail=0

# FIXME: find writable directories on other partitions
# and run the test in those directories, too.

: ${TOUCH_DIR_LIST=.}

framework_failure=0

for d in $TOUCH_DIR_LIST; do
  rm -rf $d/a $d/b
  > $d/a || framework_failure=1
  test -f $d/a || framework_failure=1
  > $d/b || framework_failure=1
  test -f $d/b || framework_failure=1
done

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

echo sleeping for $SLEEP_SECONDS seconds...
sleep $SLEEP_SECONDS
for d in $TOUCH_DIR_LIST; do
  touch $d/a || fail=1
  set x `ls -t $d/a $d/b`
  test "$*" = "x $d/a $d/b" || fail=1
done

echo sleeping for $SLEEP_SECONDS seconds...
sleep $SLEEP_SECONDS
for d in $TOUCH_DIR_LIST; do
  touch $d/b
  set x `ls -t $d/a $d/b`
  test "$*" = "x $d/b $d/a" || fail=1

  rm -rf $d/a $d/b
done

if test $fail != 0; then
  cat 1>&2 <<EOF
*** This test has just failed.  That can happen when the test is run in an
*** NFS-mounted directory on a system whose clock is not well synchronized
*** with that of the NFS server.  If you think that is the reason, set the
*** environment variable SLEEP_SECONDS to some number of seconds larger than
*** the default of $DEFAULT_SLEEP_SECONDS and rerun the test.
EOF
fi

exit $fail