Bash

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: Switch to developer user 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. ...

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. ...

Learn how to configure Ansible to connect to hosts behind a bastion or jump host by customizing your ssh_config and ansible.cfg files.

A quick tip on how to list files with their octal permissions in bash using the stat command.

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. On Linux You will need inotify-tools package: Install inotify-tools on Linux sudo apt-get install -y inotify-tools Then run something like this: ...

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: ...

A quick guide to installing and using Docker Compose for automating multi-container Docker applications, including command examples and a sample configuration file.

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: ...

On Debian in default installation you have different configuration files for PHP in Apache, FPM, CLI, etc. But on CentOS you have only one php.ini for all of them. In case I have, I need to have different configuration file for scripts running in CLI mode (more memory, etc). I could run it like this: php -c /etc/php-cli.ini script.php But this a little burdensome. So I do it like this: ...