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Copy tmux Scroll Buffer to a File

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tmux is super handy for long running commands. Especially if you have a dodgy connection which is likely to break: the command will keep running and you can re-attach to the session to save the day. But as a dyed-in-the-wool bash user, I've kinda got used to being able to scroll up and down my … Read more

HEREDOC operators

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Basic usage Output alternatives: Can also use >> to append to output file, or | tee to output to screen as it runs. Quoting preserves content If you're outputting a script you might need to preserve the variable notation instead of evaluating it. You can use either single or double quotes to do this. Zapping … Read more

rrsync: a hidden gem

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I've been using rsync for decades, and had never come across its cousin rrsync, until a google search put it on my map. I was revisiting the inherent security problem in rsync backups: if you've given ssh access to a server, it can typically do a lot more than just rsync. To limit the damage, … Read more

Advanced Bash logging to handle errors.

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So we've all done a quick log from a bash script, which looks like this 

LOGFILE="logs/$(date +%F)_backup.log"
# Append to the file
restic backup /etc/ >> $LOGFILE
find /root/scripts/ -type f -name "restic*.log" -mtime +14 -delete -print >> $LOGFILE

That's great for small scripts. But sometimes you find that its not logging errors, which are also helpful, and you need to add those:

LOGFILE="logs/$(date +%F)_backup.log"
# Append to the file
restic backup /etc/ 2>&1 >> $LOGFILE
find /root/scripts/ -type f -name "restic*.log" -mtime +14 -delete -print 2>&1 >> $LOGFILE

And different commands behave differently, so it all starts to become complicated. But there's an easier way. Two actually. The first is to use curly brackets to contain all the commands you want to log, and then pipe it through tee at the end. Commands after that block won't be logged.

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