Over on Twitter I was having a discussion about creating a mollyguard to protect yourself from accidentally rebooting the wrong machine by requiring you to type the hostname of the machine you wanted to reboot. If you need such, you can add these functions to your ~/.bashrc or ~/.profile to create such a reboot function. Note: The function shown on Twitter had the logic reversed so make sure you get the "=" and "!=" correct. If $1 equals the hostname, you want to proceed with the shutdown; if they are not equal you want a warning.

reboot() { [ "x$1" = "x$(hostname)" ] && sudo /sbin/shutdown -r now || echo "Failed to specify $(hostname)" ; }
halt() { [ "x$1" = "x$(hostname)" ] && sudo /sbin/shutdown -p now || echo "Failed to specify $(hostname)" ; }

If you run on OpenBSD you can specify doas instead of sudo.

While I'm not sure when others would use this I wanted to find the Nth word of a text file so I used this to find the, say, 318th word of the document:

user$ tr -cs "a-zA-Z'" '\012' < document.txt | sed -n '318{p;q;}'

Yes, it can get tripped up by non-Latin characters, hyphenated words, or other edge-cases, but for my 7-bit ASCII input text, it did the job.

Occasionally I have multiple windows open in vim and want to add all of those files to git. Rather than specifying each filename explicitly, I use this:

:windo !git add %

Occasionally I want to diff one or more files in git and, if everything looks good, then add them. To do so, I often take advantage of bash's ^ notation to do a replacement:

user$ git diff -- file1.txt file2.txt
user$ ^diff^add
user$ git commit -m "Looks good to me"

The second command replaces diff with add turning the command into git add -- file1.txt file2.txt without having to retype the entire command.

I have directories with lots of image files (or mail files), some of which I hard-link into other directories to save space or make sure they're in sync. How much space am I saving by hard-linking?

user$ (du -sl ; printf '-\n' ; du -s) | awk '{print $1}' | paste -s - | bc

With a little math, most of it can happen in one awk statement:

user$ (du -sl ; du -s) | awk '{t+=(-NR*2+3)*$1} END{print t}'

Overview

The remind calendar utility offers an amazing degree of power for doing calendar-related scheduling unmatched by any other calendar program I've used. If you haven't encountered it before, this presentation (PDF) gives a good overview of some of the features, as do Linux Journal and 43 Folders. In this post, I'll walk through how I use both the basic and advanced features.

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