The Linux find command can be used for searching files and directories and performing subsequent operations on them.
If you use the find command to recursively search for some files and then pipe the result to the grep command, by doing this you will actually parse the file paths/names but not their contents.
This short note shows how to recursively find files by name and grep their contents for some word or pattern. (more…)
The easiest way to get a list of all Jenkins jobs is by executing an appropriate Groovy script using a Jenkins script console feature.
This note shows two examples of Groovy scripts for listing the Jenkins jobs.
The first script simply prints the list of all Jenkins jobs while the second one additionally lets you to identify how the last build of each job was triggered, e.g. manually by user, triggered by commit, by schedule etc. (more…)
An umount command is used to unmount a device/partition by specifying the path to the directory where it has been mounted.
Sometimes, when you run the umount command you may receive the “target is busy” or “device is busy” errors indicating that there is some process that is using the mounted filesystem or the remote file server is not responding for some reason.
Luckily, it is possible to run the umount command forcefully and this short note shows how to do this safely. (more…)
A reverse name resolution zone file is used to translate an IP address in a particular namespace into a fully qualified domain name (FQDN).
If this file has been configured on a name server, it becomes possible to find a hostname from an IP address.
This note shows how to get a hostname from an IP address from the command line in Windows, Linux or MacOS using the nslookup command.
Cool Tip: How to setup a reverse name resolution! Read more →
Execute the nslookup command as follows from a terminal in Linux/MacOS or from a command prompt (CMD or PowerShell) in Windows to find the hostname by IP:
$ nslookup 192.168.0.15
- sample output -
Server: router.net.infra
Address: 192.168.0.1
Name: my-box-hostname.net.infra
Address: 192.168.0.15
The command above performs the reverse lookup and converts the IP address to hostname by querying the name server for the 15.0.168.192.in-addr.arpa record.
Out of the box, there is a Namespace called ‘default‘ in a Kubernetes cluster.
By default, the kubectl command interacts with this ‘default‘ Namespace, but it can be changed to any other Namespace.
In this note i will show how to set the default Namespace in Kubernetes. (more…)
A named screen session can be started by using the screen -S <sessionName> command.
If you start a simple screen session, by default, it will be named as something like 55355.pts-0.hostname.
No matter how the screen session has been started, it can be easily renamed at any time.
This short note shows how to rename a GNU screen session in Linux. (more…)
If your computer is running in a corporate environment, one day you may wonder which Active Directory (AD) groups your current user is a member of.
The easiest way to see what AD groups i am a member of is by executing the appropriate commands from a command prompt (CMD or PowerShell) and this short note shows how to do this. (more…)
A newline (also known as a line ending, end of line (EOL) or line break) is a character used to represent the end of a line of text and the beginning of a new line.
Text files created on DOS/Windows machines have different line endings than files created on Unix/Linux.
This note shows how to find out the line endings in a text file and how to change them. (more…)
A password-based authentication is often a default way to connect to a remote host over SSH.
But as it requires a user to enter a password manually, this creates some complicity if you need to automate the SSH login.
This note shows how to login over SSH by passing the password as a parameter on a command-line using the sshpass command. (more…)
An Ansible’s “dry run” or check mode feature is just a simulation of the execution of the ansible-playbook command.
When the ansible-playbook command is executed in the check mode, it will not make any changes on a target system.
With the Ansible’s “dry run” feature you can see if the target system is getting changed or not before actually applying the playbook and making any changes on the target host. (more…)