Bash

Learn how to uninstall a Homebrew formula along with its dependencies on MacOS, ensuring a clean removal and freeing up disk space.

Learn how to remove geo-localization and EXIF data from photos using ImageMagick on Linux, ensuring privacy before sharing images publicly.

Learn about the initial steps and adjustments needed when transitioning from a Linux desktop to MacOS for business purposes, including tips on keyboard shortcuts, application compatibility, and system settings.

It happen to me all the time that one of developers notifies me about some kind of problem that I can’t confirm from my account. Sometimes it was because of bad ssh keys configuration, other times file permissions, mostly such stuff. It’s sometimes convenient to “enter into someone’s shoes” to see what’s going on there. If you’re root on machine you may do that like this: su developer - Easy one but that’s not enough for all cases. When you use bastion host (or similar solutions) sometimes users have connection problems and it’s harder to check. When such user have ForwardAgent ssh option enabled you may stole this session to check login problems. After you switch to such user, you may wan’t to hide history (it’s optional 😉 ) - disable history like that: ...

Virtualenvs in python are cheap but from time to time you will install something with pip on your system and when time comes removing all this crap could be difficult. I found this bash snippet1 that will uninstall package with all dependencies: Recursive pip uninstall for dep in $(pip show python-neutronclient | grep Requires | sed 's/Requires: //g; s/,//g') ; do pip uninstall -y $dep ; done pip uninstall -y python-neutronclient Depending how you installed it, you might need to use sudo. ...

When you deploy your application in cloud you don’t need and don’t want your hosts exposed via SSH to the world. Malware scans whole network for easy SSH access and when find something will try some brute force attacks, overloading such machines. It’s easier to have one exposed, but secured host, that doesn’t host anything and is used as proxy/gateway to access our infrastructure- it’s called bastion host  external link . ...

Sometimes it’s easier to use octal file permissions but they’re not so easy to list. I caught myself few times that I didn’t remember how to list them - so this is a reason for that note. stat -c "%a %n" * 755 bin 755 games 755 include Yes, it’s that easy 😃 And here also with human readable attributes: stat -c '%A %a %n' * drwxr-xr-x 755 bin drwxr-xr-x 755 games drwxr-xr-x 755 include

I’m playing a lot with Docker lately. Building images, and then rebuilding, and then building again… It’s pretty boring. To automate this task a little I used inotify to build automatically after I changed any file. This trick could be used in many different situations. You will need inotify-tools package: sudo apt-get install -y inotify-tools Then run something like this: while inotifywait -e modify -r .; do docker-compose build; done This commands will rebuild my Docker images after any file change in current directory. Use Ctrl+c to exit from loop. ...

I never tried it before but today I needed to install WordPress… From command line only. And there is a way to do this with wp-cli  external link . WP-CLI installation First some requirements (as root): apt-get install php5-cli php5-mysql mysql-client curl And now installation of wp-cli (as root too): curl -O https://raw.githubusercontent.com/wp-cli/builds/gh-pages/phar/wp-cli.phar chmod +x wp-cli.phar mv wp-cli.phar /usr/local/bin/wp Check if it’s working: ...

Sometimes deployment process or other heavy task may cause some Nagios checks to rise below normal levels and bother admin1. If this is expected and you want to add downtime on host/service during this task you may use this script: #!/bin/bash function die { echo $1; exit 1; } if [[ $# -eq 0 ]] ; then die "Give hostname and time in minutes as parameter!" fi if [[ $# -eq 1 ]] ; then MINUTES=15 else MINUTES=$2 fi HOST=$1 NAGURL=http://nagios.example.com/nagios/cgi-bin/cmd.cgi USER=nagiosuser PASS=nagiospassword SERVICENAME=someservice COMMENT="Deploying new code" export MINUTES echo "Scheduling downtime on $HOST for $MINUTES minutes..." # The following is urlencoded already STARTDATE=`date "+%d-%m-%Y %H:%M:%S"` # This gives us the date/time X minutes from now ENDDATE=`date "+%d-%m-%Y %H:%M:%S" -d "$MINUTES min"` curl --silent --show-error \ --data cmd_typ=56 \ --data cmd_mod=2 \ --data host=$HOST \ --data-urlencode "service=$SERVICENAME" \ --data-urlencode "com_data=$COMMENT" \ --data trigger=0 \ --data-urlencode "start_time=$STARTDATE" \ --data-urlencode "end_time=$ENDDATE" \ --data fixed=1 \ --data hours=2 \ --data minutes=0 \ --data btnSubmit=Commit \ --insecure \ $NAGURL -u "$USER:$PASS"| grep -q "Your command request was successfully submitted to Nagios for processing." || die "Failed to con tact nagios"; echo Scheduled downtime on nagios from $STARTDATE to $ENDDATE Threat this script as template with some tips: ...