The easiest way to tell which shell you are using is by looking at what the exe link points to in your shell process’s /proc directory. You can use the command ls -l /proc/$$/exe. Below is an example: $ ls -l /proc/$$/exe lrwxrwxrwx 1 tyler tyler 0 Sep 22 19:39 /proc/19867/exe -> /bin/bash The special… Read More »
Listing all users on Linux is best done with the getent passwd command. This isn’t the only way, but it should work an practically any system. Unlike other methods, it uses your systems /etc/nsswitch.conf configuration to show users from all sources. The format is the format used in the file /etc/passwd. $ getent passwd root:x:0:0:root:/root:/bin/bash… Read More »
Linux ACL permissions are based on the draft POSIX 1003.1e. Even though ACLs are in use, the standard never made it out of the draft status. I assume you have a solid grasp on regular file permissions. If not, I suggest reading my guide on the topic before working with ACLs. Use Cases Access control… Read More »
Listing files in a package with dnf is easy. Just follow the example below: # dnf repoquery -l crontabs Last metadata expiration check: 0:12:18 ago on Sat 04 Jan 2020 09:40:27 AM EST. /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly /etc/crontab /etc/sysconfig/run-parts /usr/bin/run-parts /usr/share/licenses/crontabs /usr/share/licenses/crontabs/COPYING /usr/share/man/man4/crontabs.4.gz /usr/share/man/man4/run-parts.4.gz Replace crontabs with the name of the package you wish to… Read More »
With both DNF and YUM, there are three ways to remove repositories. One of the methods is specific to RHEL. If you are on a system that doesn’t have the dnf command, you can use the yum command instead. Using subscription-manager The subscription-manager program is specific to RHEL and specific to repositories maintained by Red… Read More »
Listing installed packages with dnf is straightforward. Unlike rpm, dnf also shows you the repository packages were installed from. The following example demonstrates listing all packages installed on a system. # dnf list installed Installed Packages acl.x86_64 2.2.53-1.el8 @anaconda audit.x86_64 3.0-0.10.20180831git0047a6c.el8 @anaconda audit-libs.x86_64 3.0-0.10.20180831git0047a6c.el8 @anaconda The left column displays the name of the package along… Read More »
There are a few ways to add a user to a group in Linux. I will cover two methods using the command line. Both methods require the ability to use the root account or the sudo command. Desktop environments often have GUI tools to do this. If you wish to use the GUI, check your… Read More »
To create a symbolic link on a UNIX or Linux system, use the ln command with the -s option. You may see or hear a symbolic link referred to as a soft link or symlink. All three terms mean the same thing. Here is an example: $ ln -s file_name link_name $ ls -l total… Read More »
Zipping a Folder Use the zip command with the -r option to zip a folder on a Linux system. For example, to zip a folder named bigfiles, you would use the following command: $ zip -r bigfiles.zip bigfiles adding: bigfiles/ (stored 0%) adding: bigfiles/bigfile2 (deflated 98%) adding: bigfiles/bigfile3 (deflated 96%) adding: bigfiles/bigfile1 (deflated 97%) After… Read More »
To rename a file in Linux, you use the mv command. The mv command can also rename directories and move files into different directories. When using mv, always specify the current filename first, followed by one or more spaces, and last the new name. For example, to rename a file named my_file.pdf to your_file.pdf, use… Read More »