pastie.org shell script

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I wrote a bash script to create new pastes on pastie.org. It features automatic source language selection based on the file extension and has a switch to make a private paste.

$ pastie --help
Usage: pastie [options] [files...]

Options:
    -h, --help          display this help
    -l, --lang    set language of the paste
    -p, --private       make paste private

If --lang is not specified, this script will try to determine the type of each
file automatically based on the extension. If no files are given on the
command line it reads from standard input.

You can download it here:
http://pastie.org/904797

The script is public domain, so do whatever you want with it.

Although this is the initial release, I bumped the version number to 1.6 already. During testing the script I pasted itself several times to pastie.org. I set a arbitrary higher version number to avoid confusion in case the previous pastes ever turn up in Google or wherever.

Update:
Seems like their parser for shell is a bit broken and doubles the heredoc starting and ending sequences in the output. For whatever reason it appears as “<<END<<END”. Please use the raw version for download instead of copy & paste.

Calculating sum of numbers in the shell

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More than one time I wanted to sum up numbers in the shell.

Imagine a command producing a list of numbers like this:


$ ...
42
23
966
1764
529
4711

Now calculating the sum of these numbers is not trivial. Using tools like bc or calc directly is not possible because you would need to put plus signs between the numbers first. So you could probably replace all ‘\n’ with ‘+’ with tr — but not the last one as that would lead to a syntax error later. Or as an alternative you could write a long shell construct with while read ... etc. In short this is just getting way too complicated for such a simple task.

Here is the simple solution in awk:


$ ... | awk 'BEGIN {total = 0} {total += $1} END {print total}'
8035

bzr shelve improved in 2.1.0

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Sometimes I was a bit frustrated that bzr does not support hunk splitting during selection changes with bzr shelve, as does git commit --interactive. Now with bzr 2.1.0 there is a new option available to launch an external editor to shelve changes as you like.

Just add the option change_editor to your ~/.bazaar/bazaar.conf in the [DEFAULT] section.

For example:


[DEFAULT]
change_editor = vimdiff -f @new_path @old_path

Alternatively, you can of course use meld or kdiff3 as well as change_editor, which will be a lot easier to use for beginners.

The placeholder @new_path will automatically be replaced with the path of the new version and @old_path with the path of the old version. With this configuration, there will be a new choice “e” during shelve:

...
Shelve? [yNefq?]

Entering “e” will start vimdiff in a two column view with the new version to the left and the old version to the right. You should read :help diff in vim to get more information about this mode. Basically you can obtain changes from the other buffer using do (“diff obtain”) and put changes to the other buffer using dp (“diff put”). Note that the old version on the right will be read-only and you are not supposed to change it. Also do not make unrelated changes or introduce new differences as that will result in conflicts on bzr unshelve later.

When you are fine with the changes exit the editor with :wqa. After confirming the shelve once more, you will see the left file as the new version in the working tree and every difference to the right file will be shelved.

Unfortunately this is not yet documented in bzr itself at the time of this writing.

Why I like bzr better than git

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Many people I know are using git as VCS and like it a lot. Although I used git in the past and still use it from time for time for some open source stuff, I was never a part of the hype on promoting git and bashing bzr.

Instead, after too much struggling with git, I totally turned to bzr now. Why? Now that’s what this post is about.

Continue reading →

Hiding MOTD on bash startup

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Usually bash displays /etc/motd at the time of last login on opening a new shell. I do not find that information very useful, as I am opening new shells a lot, so the time does not really mean anything for me. Also, the MOTD rarely changes.

There is a feature in bash to hide these messages by creating a file ~/.hushlogin. This will make bash jump right to the first prompt without any output before.

But just in case the MOTD changes and includes important messages, I enhanced this setup a little bit. Instead of just touching the .hushlogin file, I am storing the old MOTD in it. At startup the old and current MOTD is compared against each other and will be displayed only if it differs. To avoid accidentally missing the MOTD, bash will also ask for my confirmation that I have read it.

Here is the snippet from my ~/.bashrc:

# Show motd only if necessary
cmp -s $HOME/.hushlogin /etc/motd
if [ $? != 0 ]; then
    echo -e "\n==> !!! IMPORTANT: /etc/motd changed !!! <==\n"
    cat /etc/motd
    echo -e "\n==> !!! IMPORTANT: /etc/motd changed !!! <==\n"
    read -e -n 1 -p "Show again? (Y/n) " ans
    if [ "$ans" == "n" ]; then
        cat /etc/motd > $HOME/.hushlogin
    fi
fi

Please note: If you are going to use this, make sure it will not get executed on non-interactive shells. Otherwise it can break tools like scp, sftp or rsync. To ensure this will not be used on non-interactive shells, I am using this conditional at the top of my ~/.bashrc:

if [[ $- != *i* ]] ; then
    # Shell is non-interactive.  Be done now!
    return
fi