If you're new to Linux or Unix-like systems, you've probably heard of Bash and shell scripting. Bash is the most common shell for Linux and Unix systems, and it's used for managing files, running programs, and automating tasks. In this blog post, we'll cover the basics of Bash and shell scripting.
Workflow
Navigation through the file-system
The first thing you need to know is how to navigate the file system. To do this, you need to use the cd command. The cd command stands for "change directory," and it allows you to move around the file system. For example, to move to the root directory, you would type cd /.
View and list directory content
To view the content of a directory, you need to use the ls command. The ls command lists the files and directories in the current directory. To list all files and directories, including hidden ones, you can use the -a flag, like this: ls -a.
Handling Files
To create a new file, you can use the touch command. For example, to create a new file called "example.txt," you would type touch example.txt. To delete a file, you can use the rm command. For example, to delete the "example.txt" file, you would type rm example.txt.
Find Files and Directories, and Compare
It is crucial to be able to find the files and folders we need. Once we have gained access to a Linux based system, it will be essential to find configuration files, scripts created by users or the administrator, and other files and folders. We do not have to manually browse through every single folder and check when modified for the last time. There are some tools we can use to make this work easier.
View File Content
View the content of a file, you can use the cat command. For example, to view the content of "example.txt," you would type cat example.txt. You can also use the less command to view the content of a file. The less command allows you to view the content of a file one page at a time. For example, to view the content of "example.txt" using the less command, you would type less example.txt.
Edit File Content
To edit the content of a file, you can use a text editor. There are many text editors available for Linux and Unix systems, but the most common ones are vi and nano. To edit a file using nano, you would type nano example.txt. To edit a file using vi, you would type vi example.txt.
System Management
Monitoring Programs
To monitor running programs, you can use the top command. The top command shows a real-time list of the processes running on your system. To exit the top command, you can press q.
The ps command is used to display information about running processes. With this command, you can see the process ID, user, CPU and memory usage, and more. The top command provides real-time system monitoring of the processes, including the CPU and memory usage. Additionally, the htop command provides a more user-friendly interface for process monitoring.
Mounting Media
To mount a media device, such as a USB drive or CD-ROM, you can use the mount command. For example, to mount a USB drive, you would type mount /dev/sdb1 /mnt/usb. To unmount the USB drive, you would type umount /mnt/usb.
The mount command is used to mount storage devices such as hard drives, USB drives, and network shares. When a storage device is mounted, it is accessible as if it were part of the file system.
Package Management
To manage software packages on your system, you can use a package manager. The most common package managers for Linux and Unix systems are apt and yum. To install a package using apt, you would type sudo apt install packagename. To install a package using yum, you would type sudo yum install packagename.
Service and Process Management
Services are background processes that run on the system and provide various functionalities. The systemctl command is used to manage services and can be used to start, stop, restart, and enable or disable services.
Processes, on the other hand, are running instances of a program. The kill command is used to terminate a process, and the killall command is used to terminate all instances of a process. You can also use the nice command to set the priority of a process.
User Management
The useradd command is used to create a new user account on the system, and the userdel command is used to delete a user account. The passwd command is used to change a user's password.
Working with Web Services
The curl command is a powerful tool for transferring data to and from web servers. It can be used to download files, send data to web forms, and perform various other web-related tasks. The wget command is similar to curl, but it is designed specifically for downloading files.
Conclusion
Bash and shell scripting are essential skills for any Linux or Unix system administrator. With the above-mentioned commands and techniques, you can navigate the file system, manage files and processes, and perform various system management tasks efficiently. There is a lot more to learn about Bash and shell scripting, but this post should give you a solid foundation to start with.