emre şahin's digital garden 🍃 - CLI

Activate left window when the current one is closed in tmux

Emre Şahin — 2022-02-16T07:08:25+00:00

When I close a window in tmux, it typically activates the window to its right. I prefer the previously active window to be activated instead. I couldn’t find a direct setting for this, but tmux provides hooks for various events. By setting the window-unlinked hook to trigger last-window, I can achieve the desired behavior.

Add the following to your .tmux.conf:

set-hook -g window-unlinked 'last-window'

TIL: sed

Emre Şahin — 2020-07-15T15:51:00+00:00

When I try to use sed to find and edit multiple files, I always remember that perl -pe is better suited for this task. Today, this happened again. I tried to find and replace lines starting with # Bla bla with title: Bla bla, and it was easier to use perl -pe 's|^#+ (.*)|title: $1|g' than identifying what kind of regular expressions sed uses.

It’s possible to get a section from a Markdown file with a command like:

sed -n -e '/^#/,/^#/p'

It is also possible to use line numbers instead of regexes. The p at the end is the print command, which can be replaced by, for example, d to delete the lines.

telegram-send

Emre Şahin — 2020-05-12T18:47:24+00:00

There is a small Python command-line program called telegram-send that allows you to send messages to your Telegram account.

First, you need to register a new bot with @BotFather and get an API token. Then, run pip3 install --user telegram-send and prepare a config file at ~/.config/telegram-send.conf:

[telegram]
token = 
chat_id =

You’ll need to start a conversation with the bot and find your user ID (which is identical to the chat ID for the conversation you start with the bot).

After that, you can send yourself messages from the CLI like this:

telegram-send "Hello Telegram."

You can also send Markdown-formatted messages, audio, stickers, and more using various command-line options:

usage: telegram-send [-h] [--format {text,markdown,html}] [--stdin] [--pre]
                     [--disable-web-page-preview] [--silent] [-c]
                     [--configure-channel] [--configure-group]
                     [-f FILE [FILE ...]] [-i IMAGE [IMAGE ...]]
                     [-s STICKER [STICKER ...]]
                     [--animation ANIMATION [ANIMATION ...]]
                     [--video VIDEO [VIDEO ...]] [--audio AUDIO [AUDIO ...]]
                     [-l LOCATION [LOCATION ...]]
                     [--caption CAPTION [CAPTION ...]] [--config CONF] [-g]
                     [--file-manager] [--clean] [--timeout TIMEOUT]
                     [--version]
                     [message [message ...]]

Backup Script for Recent Files

Emre Şahin — 2014-02-01T22:00:00+00:00

I decided to write a script to back up only recent files. There are solutions based on unison that work periodically for all files, but as I change projects, I need to configure new backups for these projects as well. This is cumbersome and error-prone; it is easy to forget to add new artifacts to backup scripts and lose them in an emergency.

Therefore, I decided that a small Bash script using rsync and find would work better. It monitors my entire home directory and backs up recent files.

The following script does exactly that:

#!/bin/bash

if [ "x$1" = "x" ] ; then
    TARGET=/media/augustus/backup-recent-`hostname`
else
    TARGET=$1
fi

PERIOD=15

mkdir -p $TARGET

# Delete files older than $PERIOD days
find $TARGET -ctime +$PERIOD -print -delete

# Copy files newer than $PERIOD under ~. Ignore files under .hg
for d in ~/*/ ; do
    find $d -path '*/.hg/*' -prune -o -type f -ctime -$PERIOD -print  -exec rsync -aRv {} $TARGET/ \;
done

It checks whether a command-line option is provided as the target; otherwise, it sets a default target. /media/augustus/ is an NFS mount in my case, but you can specify any path.

PERIOD is the number of days that the script considers recent. Currently, it backs up files changed in the last 15 days.

The script deletes older files from the backup. Since I use other solutions for long-term storage, I don’t want to keep them here, especially since this script runs via cron every two hours.

Note that the script only checks directories under the home directory, so files located directly in the home directory are not backed up.

It also skips files under .hg directories. You can add more -prune options to the find command to exclude other irrelevant directories from your backup.

Shell (Bash and Zsh) Notes

Emre Şahin — 2013-08-16T21:00:00+00:00

Don’t use `~` in scripts; use `$HOME`

I have used ~ several times in scripts, but it may not always expand as expected depending on the environment. Use $HOME to refer to the home directory; it is much more reliable and always works.