Linux shell commands are commands that are executed in a command-line interface (CLI) in a Linux operating system. Here are some commonly used Linux shell commands:

ls: lists the files and directories in the current directory
cd: changes the current directory to the specified directory
mkdir: creates a new directory
rm: removes a file or directory
cp: copies a file or directory
mv: moves a file or directory
cat: displays the contents of a file
grep: searches for a pattern in a file or output
ping: tests connectivity to a network host
ssh: logs in to a remote server via Secure Shell (SSH) protocol
top: displays system information and processes in real-time
df: shows the amount of disk space used and available on a file system
chmod: changes the permissions of a file or directory
chown: changes the ownership of a file or directory
tar: archives files and directories into a tarball.

These are just a few examples of the many Linux shell commands that are available. To learn more about Linux shell commands, you can explore the Linux man pages, which provide detailed documentation and usage examples for each command.