zforce.in

GNU 系统开发的基于Iz77语法的压缩 学习lz77压缩算法

:
#!/bin/sh
# zforce: force a z extension on all gzip files so that gzip will not
# compress them twice.
#
# This can be useful for files with names truncated after a file transfer.
# 12345678901234 is renamed to 123456789012.z

x=`basename $0`
if test $# = 0; then
  echo "force a '.z' extension on all gzip files"
  echo usage: $x files...
  exit 1
fi

res=0
for i do
  if test ! -f "$i" ; then
    echo ${x}: $i not a file
    res=1
    continue
  fi
  test `expr "$i" : '.*[.-]z$'` -eq 0 || continue
  test `expr "$i" : '.*[.]t[ag]z$'` -eq 0 || continue

  gzip -t "$i" 2>/dev/null || continue

  if test `expr "$i" : '^.............$'` -eq 13; then
    new=`expr "$i" : '\(.*\).$`.z
  else
    new="$i.z"
  fi
  if mv "$i" "$new" 2>/dev/null; then
    echo $i -- replaced with $new
    continue
  fi
  new=`expr "$i" : '\(.*\)..$`.z

  if mv "$i" "$new" 2>/dev/null; then
    echo $i -- replaced with $new
    continue
  fi
  res=1; echo ${x}: cannot rename $i to $new
done
exit $res