Sams Teach Yourself Shell Programming in 24 Hours, Second Edition

Hour 13

1:	Add tar file extraction to the mytar script. Assume that the -x option indicates that the user wants to extract tar files and that the correct value of TARGS for extracting tar files is -xvf.
A1:	One correct implementation is as follows: #!/bin/sh USAGE="Usage: `basename $0` [-c|-t] [files|directories]" if [ $# -lt 2 ] ; then echo "$USAGE" ; exit 1 ; fi case "$1" in -t|-x) TARGS=${1}vf ; shift for i in "$@" ; do if [ -f "$i" ] ; then FILES=`tar $TARGS "$i" 2>/dev/null` if [ $? -eq 0 ] ; then echo ; echo "$i" ; echo "$FILES" else echo "ERROR: $i not a tar file." fi else echo "ERROR: $i not a file." fi done ;; -c) shift ; TARGS="-cvf" ; tar $TARGS archive.tar "$@" ;; *) echo "$USAGE" exit 0 ;; esac exit $?
2:	Add the extract option to ...