Description of problem:
At some situations, virt-tar-in/virt-tar-out/virt-copy-in/virt-copy-out will output some misunderstanding error messages due to the simple wrapper around the guestfish. I have wrote another simple wrapper to guestfish, it can improve this situation and give a proper error message. I have tested this version of wrapper, it works well, it can also used to virt-tar-out/virt-copy-in/virt-copy-out. Here is the new wrapper:

base_name="$(basename $0)"
requiredarg()
{
    [ -z "$2" ] && {
        echo "$base_name: option requires an argument -- '${1//-/}'" >&2
        echo "Try \`$base_name --help' for more information." >&2
        exit
    }
    
    add_disk="$1 $2"
    ((args++))
}

while [[ -n $1 ]]; do
    args=1
    case "$1" in
        -h | --help )
            exec man "$base_name"
            ;;
        -a | -d)
            requiredarg "$@"
            ;;
        -+ )
            echo "$base_name: invalid option -- '${1//-/}'" >&2
            echo "Try \`$base_name --help' for more information." >&2
            exit
            ;;
        *)
            other_opts="$other_opts $1"
            ;;
    esac
    shift "$args"
done

[ -z "$add_disk" ] && {
    echo "$base_name: error: you must give either -a or -d options." >&2
    echo "Try \`$base_name --help' for more information." >&2
    exit
}

exec guestfish --rw -i $add_disk tar-in $other_opts
        
        
Version-Release number of selected component (if applicable):
libguestfs-tools-c-1.29.33-1.fc22.x86_64
        
        
How reproducible:
100%
        
        
Steps to Reproduce:
# virt-tar-in
libguestfs: error: no libvirt domain called 'tar-in': Domain not found: no domain with matching name 'tar-in'

# virt-tar-in Fedora-20.raw
libguestfs: error: no libvirt domain called 'tar-in': Domain not found: no domain with matching name 'tar-in'

# virt-tar-in -c
guestfish: option requires an argument -- 'c'
Try `guestfish --help' for more information.


Actual results:
As above

Expected results:
# virt-tar-in
virt-tar-in: error: you must give either -a or -d options.
Try `virt-tar-in --help' for more information.

# virt-tar-in Fedora-20.raw
virt-tar-in: error: you must give either -a or -d options.
Try `virt-tar-in --help' for more information.
        
# virt-tar-in -c
virt-tar-in: error: you must give either -a or -d options.
Try `virt-tar-in --help' for more information.


Additional info: