Work the Shell - Still Parsing the Twitter Stream
The answer isn't that hard. The stream is newest to oldest, and the message ID values are assigned sequentially by the server, so all we need to do is cache the most recent message ID we've seen after we have answered all queries. Then, on subsequent invocations, compare each query ID to the most recent we've answered. If they're greater, we need to answer them. If not, we've already done so. Like this:
if [ "$id" == "$previouslatestid" -o $answered -eq 1 ] ; then echo "already answered query \"$msg\" from $name: skipped" answered=1 else ...
The previouslatestid is what's cached. We'll also capture the most recent ID of the current wave of queries like this:
if [ -z "$latestid" ] ; then latestid=$id # store most recent ID fi
Of course, there are a few more steps. We need to grab the cached value at the beginning of the script:
if [ -f "$lastidcache" ] ; then previouslatestid="$(cat "$lastidcache")" else previouslatestid="0" fi
And, we need to save it at the end:
echo $latestid > "$lastidcache"
That's it. I've run out of space, but the full script is available at ftp.linuxjournal.com/pub/lj/listings/issue191/10695.tgz. Next month, we'll polish it a bit and see what fun we can have with a tweetbot!
Dave Taylor has been hacking shell scripts for a really long time. He's the author of the popular Wicked Cool Shell Scripts and can be found on Twitter as @DaveTaylor and more generally at www.DaveTaylorOnline.com.
Dave Taylor has been hacking shell scripts for over thirty years. Really. He's the author of the popular "Wicked Cool Shell Scripts" and can be found on Twitter as @DaveTaylor and more generally at www.DaveTaylorOnline.com.
Practical books for the most technical people on the planet. Newly available books include:
- Agile Product Development by Ted Schmidt
- Improve Business Processes with an Enterprise Job Scheduler by Mike Diehl
- Finding Your Way: Mapping Your Network to Improve Manageability by Bill Childers
- DIY Commerce Site by Reven Lerner
Plus many more.
- diff -u: What's New in Kernel Development
- Giving Silos Their Due
- What's New in 3D Printing, Part III: the Software
- Server Hardening
- 22 Years of Linux Journal on One DVD - Now Available
- Controversy at the Linux Foundation
- February 2016 Issue of Linux Journal
- Don't Burn Your Android Yet
- Firefox OS