Wicked Cool Shell Scripts: Errata

It's inevitable, even with a team of technical and copy editors and three close proofreads of the book and production galleys as the project proceeded: there are going to be some hiccups and some typos in the book. This page contains a list of all known errata reported to-date, and if you have something you've found that you think might be a problem worth including, please don't hesitate to contact me to let me know about it.

Thanks!

Page	Description	Fix
6	The book site URL is incorrectly listed as http://www.intutive.com/	I have registered the misspelled domain name and it'll work just fine, but, of course, you should use the http://www.intuitive.com/ domain instead.
13	Typo:in the script validnum the line if [ "$compressed" != "$input" ] ; then should be modified to read: if [ "$compressed" != "$1" ] ; then	Edit the script to change $input to $1 as shown.
13	Typo: ${varname:1:1} is wrong.	It should read ${varname:0:1} to access just the first character of varname
15	Parameter order is incorrect: the invocation of sed to test for a valid phone number has the "-" in the wrong place. Instead of sed 's/[^[:digit:]\(\)- ]//g' it should instead have the "-" at the beginning: sed 's/[^- [:digit:]\(\)]//g'	Edit the script as shown
16	Typo:   if [ $3 -lt 99 ] ; then should actually be testing to see if the value is less than or equal to 99:   if [ $3 -le 99 ] ; then	Edit the script to change -lt to -le throughout this script. This exact same error occurs on all three conditional tests (sheesh!)
25	Forgotten variable expansion. In the beginning of the script, there should be a line like this: normdate="whatever you called the normdate.sh script" and then later in the script the line   newdate="$(normdate "$@")" needs one additional dollar sign so things expand properly:   newdate="$($normdate "$@")"	Ah, well, make the changes indicated to fix the script up.
82	In the script for converting temperatures, there's a spare square bracket that shows up in the sed expressions. Specifically: sed -e 's/[-[[:digit:]]*//g' sed -e 's/[^-[[:digit:]]*//g' In fact, the correct expressions should be: sed -e 's/[-[[:digit:]]*//g' sed -e 's/[^-[[:digit:]]*//g'	Edit the script to remove the two spurious square brackets.
108	In the script bestcompress you might need to change the 'ls -l' in the computation for smallest file to 'ls -lf' instead. The specific lines are: smallest="$(ls -l "$name" $Zout $gzout $bzout | \ awk '{print $5"="NR}' | sort -n | cut -d= -f2 | head -1)"	Edit the script to change ls -l to ls -lf as needed.
138	In the script findsuid, a GNU-find specific permission string snuck in and might not work with all Unixes. Specifically, the line for match in $(find /bin /usr/bin -type f -perm +4000 -print) should be modified to -perm -4000 as needed.	Edit the script to change +4000 to -4000 as needed.
149	In the script verifycron, in the unusual instance when a crontab entry is supposed to occur every second of every day that the system is running, the entry is denoted with five asterisks. The published script fails in this situation because of missing quotes. In the script on line 77 there's a conditional statement: elif [ ! -z $(echo ${min%${min#?}} | sed 's/[[:digit:]]//') ] ; then To fix this, add quotes before the $( sequence and then again after the ) at the very end of the conditional.	Edit the script to add the quotes.
150	In the script verifycron there's a glitch in the day of week check. It shows: # day of week check for dowslice in $(echo "$dow" | sed 's/[,-]/ /g') ; do if ! validNum $dowslice 31 ; then if ! validDay $dowslice ; then echo "Line ${lines}: Invalid day of week value \"$dowslice\"" errors=1 fi fi done But the value 31 should instead be 7 since it's checking day of week, not day of month, at this point.	Edit the script to change the 31 to a 7.
152	In the script docron there's a glitch that shows up if you're using Mac OS X, which has a slightly different root cron format. On line 22 it lists: if [ -z $job ] ; then but for Mac OS X you should have $job in quotes, thusly: if [ -z "$job" ] ; then	If you're on Mac OS X, edit the script to add the quotes as shown.
156	In the script rotatelogs I escape the double quotes in the find conditional unnecessarily, causing the test to always return false. The old line looks like this: if [ -z $(find \"$back1\" -mtime +$duration -print 2>/dev/null) ] but it should look like this: if [ -z $(find "$back1" -mtime +$duration -print 2>/dev/null) ]	Simply delete the two backslashes and you'll be good to go.
159	In the script backup the getopts loop has a glitch which prevents you from ever seeing the usage message. It reads while getopts "o:ifn" opt; do case "$arg" in but it should read: while getopts "o:ifn" opt; do case "$opt" in to allow the usage message to appear when incorrect flags are entered.	Fix this by changing "$arg" to "$opt" in the script.
179	In the script define the reference URL at Princeton has changed. The URL in the book is: url="http://www.cogsci.princeton.edu/  cgi-bin/webwn1.7.1?stage=1&word="	This can be easily corrected by updating the URL in the script to point to webwn2.0 instead of webwn1.7.1.
181	Accuweather has changed its Web page format, breaking the script weather. The script read: sed -n '/<font class="sevendayten">/,/[^[:digit:]]<\font>/p' | \ but it should now read: sed -n '/Start - Forecast Cell/,/End - Forecast Cell/p'	Edit the script to reflect this update.
187	In the script movieinfo a closing paren in the last conditional is missing. The line in the book is: if [ ! -z "$(grep "IMDb title search" $tempout" ] ; then but it should read: if [ ! -z "$(grep "IMDb title search" $tempout)" ] ; then	Edit the script to add the closing paren to the conditional.
291	In the script addvirtual there's an incorrect test to ensure that you're running the script as root. The line in the book is: if [ $(id -u) != "root" -a $showonly = 0 ] ; then but it should read: if [ $(id -u) != 0 -a $showonly = 0 ] ; then	Edit the script to change "root" to "0".
292	The format string handed to the date command has a teeny, but important mistake. The line printed in the book is: date="$(date +%m%d%H%m ... but it should read: date="$(date +%m%d%H%M	Edit the script to change "m" to "M".