Failsafe gzip

If you try to gzip file that is currently opened by other process, your program will lose the handler and therefore will not be able to read/write to it. You can verify that the i-node (ls -li) is different after gzip.

In Solaris, you can use fuser to check what processes are currently holding on to the file.

Below script is a fail-safe version to gzip file that has no process holding on to the file.

#! /bin/ksh
#
# gzip those files that no process is holding on to it
#


PATH=/usr/bin:/bin:/usr/sbin


usage()
{
        echo "Usage: $0 -n <name> [-d <dir>] [-b] [-e] [-[1-9]]"
        echo "       -n <name>: part of the file name"
        echo "       -d <dir> : directory to search, default to current"
        echo "       -b       : begins with the <name>"
        echo "       -e       : ends with the <name>"
        echo "       -1 .. -9 : gzip compression flag, default to -6"
}


set -- `getopt n:d:be123456789 $*`
if [ $? != 0 ]; then
        usage
        exit 1
fi


finddir="."
gzip="-6"
for i in $*
do
        case $i in
        -n)
                name=$2
                findname="*${name}*"
                shift 2
                ;;
        -d)
                finddir=$2
                shift 2
                ;;
        -b)
                findname="${name}*"
                shift
                ;;
        -e)
                findname="*${name}"
                shift
                ;;
        -[1-9])
                gzip="$i"
                shift
                ;;
        esac
done


#
# checking
#
if [ -z $findname ]; then
        usage
        exit 2
fi
if [ ! -d $finddir ]; then
        echo "Error. $finddir does not exist"
        exit 3
fi


find $finddir -name "$findname" -type f 2>/dev/null | while read f
do
        pids=`fuser -u $f 2>/dev/null`
        if [ -z $pids ]; then
                echo "Running $gzip $f ... \c"
                gzip $gzip "$f"
                echo OK
        fi
done