When you run certain package management commands, such as apt-get autoremove or apt autoremove, you may receive a warning message that states “The following packages were automatically installed and are no longer required”. This warning message means that the package manager has identified packages that were installed as dependencies for other packages, but are no … Read more
In a Bash shell script, you can find the number of arguments passed to a function by using the $# special variable. The $# variable holds the number of arguments passed to the function. Here is an example of a simple function that prints the number of arguments passed to it: j find_arguments_count() { echo … Read more
To remove all files in a directory in a Unix-like system, you can use the following command: rm -rf directory_name The rm command is used to remove files or directories, and the -rf options are used to force the removal of the directory and its contents, including any files and subdirectories. Note: This command is … Read more
To restart the MySQL server on a Linux or Unix system over an SSH connection, you can use the following command: sudo service mysql restart This command uses the sudo command to run the service command with superuser privileges. The service command is used to manage system services, and the mysql argument specifies the MySQL … Read more
To extract a ZIP file in a Linux or Unix-like system, you can use the following command: unzip filename.zip This command will extract the contents of filename.zip into the current directory. The extracted files will have the same permissions and ownership as the original ZIP file. If you want to extract the contents of the … Read more
In shell scripts, using the pattern .* to match dot files (files with names starting with a dot) is considered harmful because it may include unexpected files in the match. This is because .* matches any character zero or more times, including the / character. As a result, the pattern will match hidden files and … Read more
To remove empty lines from a text file in Linux or Unix, you can use the following command: grep . file.txt > output.txt This command uses grep to search for lines that contain a period . and writes the matching lines to a new file called output.txt. This effectively removes all empty lines from the … Read more
To reload the Apache 2 HTTPD configuration file without restarting the Apache service, you can use the following command: sudo apache2ctl graceful The graceful option signals the Apache process to reload the configuration file and apply the changes without interrupting ongoing requests. This allows you to make changes to the Apache configuration file and have … Read more
To wipe all changes and undo all modifications made to a file since it was opened in the vi or vim text editor, you can use the following command: :e! This command discards all changes and reloads the file from disk, effectively undoing all changes made since the file was opened. Note: This will only … Read more
The tar command in Linux is used to create and extract archive files. To create a .tar archive file from one or more files or directories, you can use the following syntax: tar -cvf archive.tar file1 file2 directory1 In this example, -c option is used to create an archive, -v option is used for verbose … Read more