8gb

实战Linux编程的原代码,希望对学驱动的人能有所帮助

#!/bin/sh
# Ensure that du does not rely on narrow types like size_t for
# file sizes or sums.

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

. $srcdir/../envvar-check

pwd=`pwd`
t0=`echo "$0"|sed 's,.*/,,'`.tmp; tmp=$t0/$$
trap 'status=$?; cd $pwd; chmod -R u+rwx $t0; rm -rf $t0 && exit $status' 0
trap '(exit $?); exit $?' 1 2 13 15

framework_failure=0
mkdir -p $tmp || framework_failure=1
cd $tmp || framework_failure=1

if test $framework_failure = 1; then
  echo "$0: failure in testing framework" 1>&2
  (exit 1); exit 1
fi

dd bs=1 seek=8G of=big < /dev/null 2> /dev/null
if test $? != 0; then
  echo "$0: cannot create a file large enough for this test; possibly" 1>&2
  echo "$0: because file offsets are only 32 bits on this file system" 1>&2
  (exit 77); exit 77
fi

# FIXME: this should be a test of dd.
# On some systems (at least linux-2.4.18 + NFS to disks on a Solaris system)
# the `dd' command above mistakenly creates a file of length `0', yet
# doesn't fail.  The root of that failure is that the ftruncate call
# returns zero but doesn't do its job.  Detect this failure.
set x `ls -gG big`
size=$4
if test "$size" = 0; then
  echo "$0: cannot create a file large enough for this test;" 1>&2
  echo "$0: possibly because this system's NFS support is buggy;" 1>&2
  echo "$0: Consider rerunning this test on a different file system." 1>&2
  (exit 77); exit 77
fi

fail=0

# This would print `0	big' with coreutils-4.5.8.
du -ab big > out || fail=1

cat <<\EOF > exp
8589934592	big
EOF

cmp out exp || fail=1
test $fail = 1 && diff out exp 2> /dev/null

(exit $fail); exit $fail