In the Windows explorer address bar enter –
\\wsl$
Category: system admin
mesg: ttyname failed: Inappropriate ioctl for device
While running a cron job in Linux, I sometimes get this error and I had been struggling to solve this until I came across this post.
Although that particular post mentions the cause being Vagrant, mine was due to a cron job.
First the solution …
Modify .profile under home folder
Open ~/.profile
Replace the following line –
mesg n || true
with
tty -s && mesg n
The reason for this is given very well in the post linked above.
Continue readingPostgres DB migration error due to replication
We got a weird error today when running the latest migration on a production Postgres DB.
cannot update table "schema_info" because it does not have a replica identity and publishes updates
The table schema_info is created when we run ruby Sequel migrations. This table stores just the version number of the latest migration applied under a column called version.
We had set up a replica database some time ago and it looked like the issue was because of this.
Continue readingDisable specific default Windows key shortcuts
A number of times, I prefer to use the Windows key on the keyboard to create shortcuts, especially to applications which I use frequently.
However, Windows has a default set of keyboard shortcuts that it maps to various applications and those key mappings can’t be changed. A few examples are Cortana (Win+C), Clipboard (Win+V).
To get around this, the Registry Editor needs to be modified.
Continue readingusers and sudo in Linux
Every time I need to create, modify, grant sudo access to users in Linux, I have to search for it.
This is a list of the commands I’ve used in the past.
Will keep updating this so that I don’t have to load a search page every time!
All commands below are run as root user. If I’m not the root user, I need to prefix them with sudo!
Create Postgres replica on separate server over the network
A database replica is able to provide another layer of protection in case of the main database server going down.
Postgres has this capability out of the box.
In this case the requirement was to create a replica on a separate server. (It’s also possible to create it on the same server where Postgres is running).
The replica maintains an exact copy of the main database (called Primary) on a real-time basis.
Continue readingRun Postgres exposed to the internet
Although this is not recommended, there might be scenarios where there are no other options.
An example is an analysis software which doesn’t give the capability to connect via SSH. I came across this scenario when someone wanted to use QLik. Although this has a lot of capabilities, but when something like this is required, I’d rather use the open source and free Metabase.
Continue readingCompile fossil on Ubuntu Linux
Recently, I had to build fossil from source on Ubuntu because I needed to make a change to the source code.
It required a number of dependencies which is expected to be installed.
They are –
gcc (obviously!)
zlib1g and zlib1g-dev
tcl-dev
tk
libssl
libssl-dev
Setup up READ_ONLY users on Postgres
To grant access to users for only viewing a database (i.e. no INESRTs or CREATE or UPDATE access) there are certain conditions.
First, access should be only allowed through ssh.
Second, the ssh user should not be able to get into a shell directly.
And finally, the database should restrict access to that particular user with relevant permissions.
Continue readingPM2 – the best process manager
In the past, on my server I’ve installed Fossil, Syncthing, Bitwarden, Inlets. All these require some form of Process Management. These programs / processes / services need to be always running, so they are restarted in case they get terminated. Also, on a system restart these need to start up automatically.
I’ve mostly used Systemd or Supervisor to all these things.
However, I recently came across PM2 and I was really blown out of my mind as to how simple it was to set it up.
Continue reading