shell

Oooooh, the temptation level is very high on this one.

LinuxCommand.org has been running a series of posts since February 2009 on "Building An All-Text Linux Workstation." The latest, Part 14, looks at installing and running the indispensable Screen program.

Now that we have installed a bunch of interactive applications on our workstations and SSH to allow remote access, we have a slight problem. Is it reasonable for an interactive program (like mutt) monopolize our terminal session? Isn't Linux multi-tasking? On the graphical desktop, we can have many applications running at once and, by moving the mouse, we can switch from application to application. Of course, on the console, we can switch virtual terminals to provide multiple sessions and if we are using SSH, remotely accessing our workstation from a graphical desktop, we can open multiple terminal windows.

But there's another way. The screen program allows multiple sessions inside a single terminal. You can create any number of sessions and can even split screens to view two sessions at once. Further (and this is the cool part), screen allows you to "detach" a session from a terminal and later re-attach the session to a different terminal.

Yay, Screen!

Here's the very first in the series, a short introduction. This URL takes you to the whole kit and kaboodle in reverse chronological order.

I was casting around for a replacement for the excellent Tofu screen text reader for Mac, due to some encoding issues. Always wont to explore the command-line options, I turned first to the ubiquitous less pager, available on pretty much every unix-alike system out there.

The only real drawback to less is its apparent inability to wrap long lines at spaces rather than chopping words in the middle and sans hyphenation. This isn't a problem on hard-return files like a Project Gutenberg ebook, but makes for difficult reading otherwise. (The opposite is the case for Tofu, which requires a bit of manual column widening to compensate for the hard returns.)

Doing a bit of poking around, I re-discovered the also-ubiquitous fmt command, which does word wrapping to a fare-thee-well, though doesn't do paging.

Combining the two commands gives the best of both in classic Unix fashion:

fmt 1911EthanFrome.txt | less

You can also use options to enhance the experience. less -m will give you a prompt showing how far along you are in the file; see man less for others.

The pager recognizes vim movement keys, which I love. Plus you can hit the v key at any time to drop into vim, edit the file, and then return to less. Spiffy.

Of course, you could just use vim (or your favorite text editor), but I like the simplicity without the overhead. Unlike other options, less doesn't read the entire file into memory before displaying it, a definite advantage on big documents.

Another Tip: If you're in a Mac Terminal window, right click on a word or phrase to search for it in Google or Dictionary.

Bonus tangential tip: if you don't care about downloading the text files but want to stick to reading Project Gutenberg files in the terminal, why not use lynx or ELinks?

A couple of days ago, Slashdot posted a story asking about "(Useful) Stupid Unix Tricks?":

So the other day I messaged another admin from the console using the regular old 'write' command (as I've been doing for over 10 years). To my surprise he didn't know how to respond back to me (he had to call me on the phone) and had never even known you could do that. That got me thinking that there's probably lots of things like that, and likely things I've never heard of. What sorts of things do you take for granted as a natural part of Unix that other people are surprised at?

It's perhaps unsurprising that there have been over 2200 comments exploring the arcana of the Unix and Unixy command line. A lot of awesome lore to check out.

Yesterday came the next story, "(Useful) Stupid Vim Tricks?":

I thoroughly enjoyed the recent post about Unix tricks, so I ask Slashdot vim users, what's out there? :Sex, :b#, marks, ctags. Any tricks worth sharing?

570+ comments later, there's a lot to check out there as well.

Today's post was inevitable, "(Stupid) Useful Emacs Tricks?":

Since the Vi version of this question was both interesting and popular, let's hear from the other end of the spectrum. What are your favorite tricks, macros, extensions, and techniques for any of the various Emacs? Myself, I like 'M-x dunnet' ;-)

200 comments and counting.

One of the most enjoyable parts of the Vim story, apart from the various spiffy command tips and tricks, were links to other sites. Here are a couple, along with a few related others I've linked to before.

• Best Vim Tips (Wikia) (at the Vim Tips Wiki)
• Efficient Editing With vim
• GTD with Vim
• Vimperator - Firefox add-on that makes the browser look and feel like vim.
• Word War vi - "A retro styled side scrolling shoot'em up arcade game for linux. Your mission is to traverse core memory and rid the host of emacs." (See my followup post "Compiling Word War vi on Mac OS X".)
• 7 Habits For Effective Text Editing 2.0 - Bram Moolenaar on Google Video. (PDF of the presentation.)

From Mendel Cooper comes the Advanced Bash Scripting Guide: An in-depth exploration of the art of shell scripting.

This tutorial assumes no previous knowledge of scripting or programming, but progresses rapidly toward an intermediate/advanced level of instruction . . . all the while sneaking in little snippets of UNIX® wisdom and lore. It serves as a textbook, a manual for self-study, and a reference and source of knowledge on shell scripting techniques. The exercises and heavily-commented examples invite active reader participation, under the premise that the only way to really learn scripting is to write scripts.

This book is suitable for classroom use as a general introduction to programming concepts.

• Terminal Productivity Tips
  "...the most useful hints for working on the command line in the context of OS X server. It's probably aimed at people who work with Terminal every day...but have never had the time to look around for tips to boost their productivity."

• Basic Aspects of Scientific Computing on OS X
• Scientific Computing on Ubuntu

• Terminal Tip: the joy of nl - The Unofficial Apple Weblog (TUAW)
• MacOSX Guru Site: How to read local Unix mail in Mail.app under Tiger ?
• growlnotify documentation
• Technical Note TN2065: do shell script in AppleScript
• Two-Heel Drive: A plug for plain ol' walking