dlclecs

#!/bin/sh

#----------------------------------------------------------------------------------
# Project Name      - miscellaneous/dlclecs
# Started On        - Tue 19 Sep 13:00:16 BST 2017
# Last Change       - Sun  8 Oct 21:02:17 BST 2017
# Author E-Mail     - terminalforlife@yahoo.com
# Author GitHub     - https://github.com/terminalforlife
#----------------------------------------------------------------------------------

# With this small shell program you can download some C programming teaching files.

#----------------------------------------------------------------------------------

XERR(){ echo "ERROR: $1" 1>&2; exit 1; }
ERR(){ echo "ERROR: $1" 1>&2; }

DEPCOUNT=0
for DEP in /usr/bin/id /usr/bin/basename /bin/grep /usr/bin/wget; do
	[ -x "$DEP" ] || {
		ERR "Dependency '$DEP' not met."
		DEPCOUNT=$(( DEPCOUNT + 1 ))
	}
done

[ $DEPCOUNT -eq 0 ] || exit 1

[ `/usr/bin/id -u` -eq 0 ] && XERR "Root access isn't required."

DOMAIN="https://ocw.mit.edu"
CATEGORY="electrical-engineering-and-computer-science"
COURSE="6-087-practical-programming-in-c-january-iap-2010"
URL1="/courses/$CATEGORY/$COURSE/lecture-notes/"
GREP_REGEX="${URL1}MIT6_087IAP10_lec"

DLINKS=$(
	/usr/bin/wget -q "$DOMAIN/$URL1" -O -\
		| /bin/grep -o "${GREP_REGEX}[0-9]\+.pdf"
)

for FILE in $DLINKS; do
	FILENAME=`/usr/bin/basename $FILE`

	/usr/bin/wget -q "${DOMAIN}${FILE}" && {
		echo "FILE: $FILENAME"
	} || {
		XERR "$FILENAME"
	}
done