Removing Line Breaks

 Posted by  Linux  No Responses »
Nov 162018
 

Sometime in scripting you don’t get to choose your input format. For example, you might get data in multiple lines when you actually need it all in a single line. For such occasions you can go with:

$ cat file | awk '{printf "%s", $0}'

Likewise you might want lines separated by a space. Slight modification makes it happen:

$ cat file | awk '{printf "%s ", $0}'

Lastly, you might want to split a single line into multiple ones (handy for base64 printouts):

$ cat file | fold -w 72

PS: Check fmt if you need word-aware line splitting.

Extracting Public Key From a Private One

 Posted by  Linux  No Responses »
Nov 112018
 

Common key management method seen in Linux scripts is copying private and public SSH key around. While not necessarily the best way to approach things, getting your private SSH key does come in handy when easy automation is needed.

However, there is no need to copy public key if you are already copying the private one. Since private key contains everything, you can use ssh-keygen to extract public key from it:

$ ssh-keygen -yf ~/.ssh/id_rsa > ~/.ssh/id_rsa.pub

What is the advantage you ask? Isn’t it easier just to copy two files instead of copying one and dealing with shell scripting for second?

Well, yes. However, it is also more error prone as you must always keep private and public key in sync. If you replace one and by accident forget to replace the other, you will be chasing your tail in no time.

Familiar Column Selection in Visual Studio Code

 Posted by  Uncategorized  No Responses »
Nov 062018
 

If you ever dealt with any advanced text editor, you are probably aware of column (a.k.a. block selection). You press Shift+Alt and then either use mouse or arrow keys to have a bit unusual block selection. While not needed often, it’s invaluable when it comes to dealing with text in columns.

Visual Studio Code does support it but, of course, there are minor issues. First of all, unlike almost any other editor (including Visual Studio!), shortcut is actually Shift+Ctrl+Alt. Fortunately this can be fixed either by manually remapping key bindings for column selection or by simply installing Visual Studio Keymap extension.

While that sorts out column selection key shortcut, it still leaves one annoying problem – if you move cursor in any direction while multiple lines are selected, you will see multiple cursors move – instead of more usual selection cancellation. Fortunately, you can add a few key bindings in keybindings.json to deal with that issue:

[
    {
        "key": "left",
        "command": "cancelSelection",
        "when": "editorHasMultipleSelections && textInputFocus"
    },
    {
        "key": "right",
        "command": "cancelSelection",
        "when": "editorHasMultipleSelections && textInputFocus"
    },
    {
        "key": "up",
        "command": "cancelSelection",
        "when": "editorHasMultipleSelections && textInputFocus"
    },
    {
        "key": "down",
        "command": "cancelSelection",
        "when": "editorHasMultipleSelections && textInputFocus"
    },
    {
        "key": "pageup",
        "command": "cancelSelection",
        "when": "editorHasMultipleSelections && textInputFocus"
    },
    {
        "key": "pagedown",
        "command": "cancelSelection",
        "when": "editorHasMultipleSelections && textInputFocus"
    }
]

Now you can enjoy block selection that works properly. :)

DRM Exceptions

 Posted by  Uncategorized  No Responses »
Nov 012018
 

A few days ago The Library of Congress has published Exemption to Prohibition on Circumvention of Copyright Protection Systems for Access Control Technologies. To make a long document short, you get to bypass a bit of DMCA (Digital Millennium Copyright Act) rules.

Most of the media talk about playing older games and fixing consoles or jail-breaking your phone but that’s not the full scope. For example, there is a security research exception. Without this exception any company ending as butt of a joke could sue the security researcher. And, the way how DMCA was written, they would prevail. Mind you, they still get to sue you, but now their victory is unlikely.

For Nth year in row, these rules also plug a hole in e-book accessibility. For example, without this exception, blind people would depend on the mercy of DRM-protected content producers. With this exception, they can use software of their choice to help them read and, if software has to break DRM to do it, so be it.

Lastly, one important category is fixing your vehicles. Quite a few manufacturers (John Deer comes first to mind but they are not alone) have been using DRM as a way to prevent you from fixing your vehicle yourself. There is quite a lot of revenue to get if you can block those pesky independent repairmen. Well, at least now they cannot use DRM to do this.

However, it’s not all good news as these provisions expire every three years and thus there is always a possibility of “LoC giveth, LoC taketh away” situation in the future. And just having right to DRM circumvention doesn’t mean shit if you still cannot get replacement parts and/or any replacement parts you do obtain are potentially seized.

But it is a good step forward.

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