Posts Tagged ‘PS1’

2011w30

Sunday, July 31st, 2011

Hacking the shell

I’ve scratched some itches this week, some by pure luck, others by seeking these itches out and scratching them with a vengeance ;)

Added to my ~/.bash_aliases is now alias pwd='pwd -P' which tells pwd to resolve the real path when you have cd’d in to a symlinked directory.

Not really a hack, but I discovered Meta-BackSpc / ESC-BackSpc which will, unlike Ctrl-w, delete parts of a path, instead of the entire path.

This thread was of great help in finding that key combination.

Also, thanks to Rikard I got hold of this document which outlines how I would go about getting a word, after the cursor, deleted. Before the cursor is eash (Ctrl-w), but after has always eluded me. Turns out it is Meta-d (or, as in my case, if that is overridden by your window manager, “ESC d”). VERY nice!

I did update my PS1 variable, both for root and my ordinary user. I don’t really know why I hadn’t thought of adding a time indicator before.

There have been times when I have started a long running process, and half an hour or so into it realized that it would have been nice to time the process. Now, this wouldn’t exactly be able to fully replace time, but could do in a pinch so to speak.

root: PS1='\n\[\e[0;33m\][\t] \[\e[0;31;5m\]\u@\h\e[25m\] \[\e[01;34m\]$(pwd)\n\[\e[0m\]# '

which will create the prompt:

[HH:MM:SS] root@host /present/working/directory
#

(yes, root@host IS blinking. root can haz be seriuz bizness!)

user: PS1='\n\[\e[0;33m\][\t] \[\e[0;37m\]\u@\h \[\e[01;34m\]$(pwd)\[\e[0m\]\n\$ '

and this produces

[HH:MM:SS] patrik@host /present/working/directory
$

ImageMagick and Animations

I kindof just assumed imagemagick would have some sort of way of creating an animated gif, and of course imagemagick didn’t let me down.

What surprised me was how incredibly easy it was.

Duck Duck Go (as I am attempting a google-free week) gave me this result, and once I had tweaked the parameters somewhat I ended up with this: $ convert -delay 50 -loop 0 root*.gif rootshell.gif

Zenity and passtore

I also managed to convince (nagged him until his ears risked falling off ;)) Rikard to try out my password management system passtore.

He did have one counter-demand however: he’d need a GUI for day-to-day operations. Me, being a wmii acolyte, can do without it, but I can see how he would feel different, and seeing as it would be a fun exercise, and I’d get him to give it a shot, I sat down and had at it.

Zenity was my first thought, and as it worked out well, it was my only thought ;) The working name for that code is “Heaven ZENt”. Yes I know, I am a stupid wanker, I can live with that ;D

I am however pondering whether I should release this code as a separate project (it depends on passtore, and is useless without it, which should indicate “no”) or not (it does introduce a dependency on zenity, which isn’t strictly needed to operate passtore).

At present time it is only a wrapper around the getpass script from passtore. In essence, “heaven ZENt” is “wyrd” to “passtore’s” “remind”. I am unsure as how to proceed. Input would, as always, be appreciated.

Musings

I’ve given myself the mission to move one of my (spam-trap) email accounts from Thunderbird to mutt. I really want to be able to use mutt as that would be one less thing I’d need to start X for.

So I am looking at other peoples .muttrc files, and came across the index_format setting. This controls how your list of emails in an “inbox” is presented. In Thunderbird this view (simplified) is “some flags, subject, some more flags, author name, even more flags, date”, and what I realize from the .muttrc files I’m viewing, is that at least some people place the date before author, before subject.

That got me thinking about whether this is some sort of brain hack, to force the brain into working in a different way. Coming from Thunderbird, when a new message arrives in a conversation my reaction is to either open it, or let it be for now, depending on whether it is a discussion I am interested in.

At that point I don’t bother to look at the author field, if the conversation is uninteresting (to me) I will simply defer it to later, and if it is interesting I will simply open the new mail and read it, thereby getting to know who wrote it.

Putting the author in front of the subject could let you filter on people rather than on subject, as we all have some people we listen more intently to than others, so whatever discussion they’re in, it might be worth while to read it.

But that still didn’t explain why they’d put date and time before author. The only idea I have about this is that some mails will be urgent and thus it is good to see when they arrived. But I don’t know. I think I will try out “flags, author, subject, datetime” and see how that goes.

Revelation

If you mess up the datetime settings in BIOS (because you have powered down and unplugged your system during a thunderstorm, AND your motherboard is so old that the CMOS battery is dead) you may experience some problems when booting.

In my particular case, FSCK (or whatever binary it is that is performing a quick check on the file system during boot) reported that the datetime was now 2011-07-11 (because I fucked that up), but the last check had been performed in 2011-07-22.

This made it confused and prompted me to manually repair the file system, by entering the root password (which I have unset, -1 for sudo / me) and doing some operations.

That was actually not such a fun night trying to get to the bottom of that.

:wq

Galactifying my desktop

Saturday, May 16th, 2009

I stumbled across a blog post today which described how to “insert” a terminal onto your Compiz desktop. Naturally I became all giddy over the idea since all these tv-shows, which present computers where the desktop is alive with various kinds of fictional data which flow by, has totally corrupted me, so I got to work setting it up per the instructions.

My previous wallpaper (white and black, and various shades of gray) didn’t make font-color selection easy, which ended up with me replacing the old wallpaper, with the beautiful Tricia Helfer (wallpaper).

Which got me thinking further, that I could do something funny with this terminal, and since my desktop was already taking on a strong feel of Battlestar Galactica (well, number six at least) I could have the terminal reinforce that feeling.

So, terminal font-color: red. Then I had another thought. Inside the .bashrc configuration file there is a small snippet of code which sets the PS1 variable to various things. Pontus has modified his, and helped me modify my, PS1 variable so that each terminal prompt now reads:

[username] [pwd]
$

Therefore it shouldn’t be that hard for me to modify it to look for this particular terminal-instance and output an altogether different prompt, say along the lines of:

By your command
>

This turned out to be a rather hard nut to crack actually. I figured I could write a shell script which would launch the terminal, with a correct set of parameters, and one of these parameters, in turn, would be another shell script to execute upon creation of the terminal window. The first shell script could then be called upon by the session manager at login.

That was the theory anyway. Actually getting it to perform all these things was less than easy. The shell script to be executed by the terminal wouldn’t conform (although this might have been my own ignorance putting a stop to it).

I won’t drag on about all the various ways I tried to fix this, in the end Pontus arrived and saved the day ;D

His solution: create a clone of the .bashrc file, change the PS1 variable modification in it to whatever I wanted (“By your command”), then have the session manager execute the following command:

gnome-terminal --window-with-profile=trans -x bash --rcfile ~/.nrsixrc

(where .nrsixrc is the cloned .bashrc file, containing the modified PS1 variable)

For interested parties, the interesting line in .nrsixrc is this one:

PS1='\nBy your command\n> '

And here’s the result:

by_your_command1 Oi! Stop ogling the b00bies and focus your attention at the upper left corner! I don’t know about you, but I find it pretty neat.

The one thing I have a hard time figuring out however, is why the terminal won’t either die, or recover, if I by accident forget myself and try to close that terminal. It will just “hang” and my two options at that time is to either use xkill (which coincidentally will also kill the terminal with which I initialize xkill) or do a killall gnome-terminal. None of these alternatives are especially attractive, and I can for the live of me not figure out why that is. But for the time being it will do just fine.