Quick Bytes IT Stuff

Setting up a new environment of Linux boxes either Physical servers, VMs or Containers, one thing to consider is how you will login or manage those devices. In Linux world, SSH is the most common way to manage headless servers or VMs. SSH keys must be added to ~/.ssh/known_hosts to preload to the host keys before connecting to the new servers. There quite a few ways to do it, via bash script, or simply logging in and copying manually the key.but quite tedious and not the practical way if there are hundreds of more servers. ssh-keyscan server1 server2 server3 >> ~/.ssh/known_hosts This will suppress the question whether you want to add the keys or not, and type yes to continue. ssh-keyscan won't require any manual intervention once the connectivity is established it will just add all the keys available on the remote servers to known_hosts. Yes rather than typing ssh-keyscan server1 server2 it would be better to have a list on a text file and use while loop to read the file and...

Bash script/command below shows how to rename multiple files. If the filename shows some pattern, then it will be easier to rename.  Example filename: file_text_a.txt file_text_b.txt file_text_c.txt file_text_etc... ... .txt Script/command below, shows some magic to rename files all at once. The command below can be integrated to a script or simply run the command on the terminal. Create some dummy files for testing before running on actual files to be renamed or in production. find . -name "*.txt" -exec sh -c '   for file; do       newf=$(echo "$file" | sed "s/text/tested/" )  &&   mv "$file" "$newf"   done ' sh {} + Output is: file_tested_a.txt file_tested_b.txt Since the command uses sed, replace 'text' with any string to be searches and replace 'tested' also with any new string for the filename. Till next time.. Enjoy Linux and scripting... Put your trust in God and have Faith. Exodus 14:14, "The...

Systemd ecosystem provides tools to manage the Linux system. Here are some quick commands to check Linux system status. systemctl -  manage system services and units timedatctl - check system time, date and NTP localectl - quickly check system locale, language, kb layout hostnamectl - check static hostname, OS, kernel, architecture x86 or x64 resolvectl - quickly check DNS IP networkctl - quickly check interfaces names, operational status of interfaces, and setup whether managed or unmanaged loginctl - check session if, username, and for how long the user is logged in journalctl - to check services logs why some services are not starting  Those are the basic and most common ones. Enjoy Linux-ing. Keep the Faith alive, Trust Jesus! God bless!

View XML code in Android Studio. By default, in Android Studio Narwhal | 2025.1.1 Patch 1 what is shown is the layout of the XML. Android Studio, provides 3 options for previewing the XML. 1 - View by code Only 2 - View with XML code and the output or the layout 3 - View only the output of the XML or view the design only To select these options once an XML or layout file is opened. The options can be found on the top right of the screen, just beside the current XML file that os being viewed. See this screenshot below on how it looks like: Hope it helps. Life is a gift. Life is a journey. Trust the Almighty, Pray always.

Finding duplicate values in Excel can easily be done using Excel Formula. Manually find duplicate values in a single column with 100 or more rows is tedious and prone to errors. Thankfully, Excel formula can do this task with precision. Assuming, the data or values has no trailing white spaces. Trailing white spaces, will cause problem because even though its whitespace still treated as a character by Excel. Data must be sanitized before comparing. Excel fomula to find Unique values or duplicates can be done using the formula below. =IF(COUNTIF($A$1:$A$13,A1)>1, "Duplicate","Unique") $A$1:$A$13 ==> Range to check duplicate or unique values, adjust the range as required A1 ==> Check duplicate values at this row or start comparing at A1 >1 ==> If there is a duplicate or a similar value more than 1, if the value is 2. Then the 3rd value that is similar to the other two will be identified as duplicate "Duplicate","Unique...

Instance store volume in AWS is not like the EBS Volume (ebs - elastic block storage). The main difference between EBS and instance store volume, is EBS data or its contents will persist after reboot or shutdown. And for EBS volume you can take snapshot, create image do a backup or simply attached the EBS volume to another instance. Where as for instance store volume, which is physically attached to the host. It can't be search or can't be found on the "Volume" navigation pane. Thus, snapshot or taking backup is not possible. Instance store volume is some sort of a RAMDisk, in which it is indeed process data quite fast. However, if the instance is rebooted or shutdown all data is gone. Ideal only for dynamic data processing, that once data is process on the fly; data can be discarded or not needed anymore. How to view or check whether the instance you have got instance store volume? In a Linux instance, type the command below on a Terminal window: lsblk -o +...

Converting column values to a single row separated by commas, is needed by some applications to iterate thru the values. Some automation tools, require such format. Example image below, shows A1 to A35 a list of Server Name. 35 rows is just an example or a demonstration it can easily become hundred of rows or more depending on the actual servers or data in the environment. To convert the rows to a single row separated by a comma, can easily be done using Excel. Excel 2019 and above is needed for the TEXTJOIN formula. Example image below, shows how to convert the Column values to a single row with comma as a delimiter. Formula is: =TEXTJOIN(",", TRUE, A1:A35) "," means separate the data with a comma "TRUE" means don't include empty spaces A1:A35 the range of values that will be converted to a single row with comma as a delimiter Image below shows the output after the formula process the data. Once you have the data as desired...

Reading uncommented line is almost a daily live for most Linux and Windows Sys Admin. Uncommented in .conf or .ini lines are the active or the lines that are currently in used for the loaded configuration. In Linux, it's quite straight forward to do it using grep. grep ^[^#] service_file.conf The above command uses regex, to search for lines in the .conf file that doesn't start with #. In regex ^ means the first character, but if it is inside the brackets it has other meaning. It negates whatever character that follows. So, the regex means search the first character that doesn't start with #. Technically, it's teling grep to search for uncommented lines. Yes, the above solution is for Linux. How can we do it in Windows? Well, it turns out to be almost the same but with a little twist of course since its a different operating system. So, here's how we can do it in Windows. findstr /b /v ^# file.txt Hopefully, it makes life easier and the above commands...

icacls is a command line utility tool that allows system admin to grant or deny access permissions to a folder or path. Example below grants the user "TheAdminUser1" to the Desktop path specified below. icacls C:\Users\admin\Desktop /grant TheAdminUser1:F To check whether the permissions has been applied or not. cd to the path, like C:\Users\admin\Desktop, then type: icacls . . >> means the current path Once everything is ok a similar output like the image below will be shown, and there should be an "F" access list which means Full Access Permissions. If the output shows "successfully processed 1 files" and failed processes shows "0" files then permission has been applied without any issues. For more complex scenarios, and if the system has PowerShell cmdlets installed like Get-Acl and Set-Acl might offer more flexibility. Cast all your anxieties on him, for he cares about you. - 1 Peter 5:7 Don't let your heart b...