I've finally gotten 'cpio' into a shape where it could be useable. This version can archive and extract directories, sockets, FIFOs, devices, symlinks, and regular files. Supported options are -iot, -H FMT (which is a dummy right now). It only writes newc, and could read newc or newcrc. This does NOT implement -d, which essentially is equivalent to mkdir -p $(dirname $FILE) for every file that needs it. Hard links are not supported, though it would be easy to add them given a hash table or something like that. I also have not implemented the "<n> blocks" output on stderr. If desired, I can add it pretty simply. There is one assumption this makes: that the mode of a file, as mode_t, is bitwise equivalent to the mode as defined for the cpio format. This is true of Linux, but is not mandated by POSIX. If it is compiled for a system where that is false, the archives will not be portable.

#!/bin/bash

[ -f testing.sh ] && . testing.sh

testing "expr integer" "expr 5" "5\n" "" ""
testing "expr integer negative" "expr -5" "-5\n" "" ""
testing "expr string" "expr astring" "astring\n" "" ""
testing "expr 1 + 3" "expr 1 + 3" "4\n" "" ""
testing "expr 5 + 6 * 3" "expr 5 + 6 \* 3" "23\n" "" ""
testing "expr ( 5 + 6 ) * 3" "expr \( 5 + 6 \) \* 3" "33\n" "" ""