Bash Script Execution Exercises, Solutions, and Explanations
1.
Write a Bash script that prints "Hello, World!" when executed.
Code:
#!/bin/bash
# Bash script to print "Hello, World!"
echo "Hello, World!"
Save the file with a ".sh" extension, for example, "test.sh".
Make the script executable by running the following command in the terminal:
chmod +x test.sh
To execute the script, navigate to the directory where the script is saved and run the following command:
./test.sh
Output:
Hello, World!
2.
Write a Bash script that echoes the current date and time when executed.
Code:
#!/bin/bash
# Bash script to echo the current date and time
echo "Current date and time: $(date)"
Save the file with a ".sh" extension, for example, "test.sh".
Make the script executable by running the following command in the terminal:
chmod +x test.sh
To execute the script, navigate to the directory where the script is saved and run the following command:
./test.sh
Output:
Current date and time: Tue Apr 16 18:45:12 IST 2014
3.
Write a Bash script that prints the contents of a file named "output.txt" when executed.
Code:
#!/bin/bash
# Bash script to print the contents of a file named "output.txt"
cat output.txt
Save the file with a ".sh" extension, for example, "test.sh".
Make the script executable by running the following command in the terminal:
chmod +x test.sh
Ensure that there is a file named "output.txt" in the same directory as the script, and it contains some text.
To execute the script, navigate to the directory where the script is saved and run the following command:
./test.sh
Output:
-rw-r--r-- 1 ad ad 67 Apr 13 18:11 error.log -rw-r--r-- 1 ad ad 284 Apr 13 17:41 file1.txt -rw-r--r-- 1 ad ad 284 Apr 13 17:41 file2.txt -rw-r--r-- 1 ad ad 284 Apr 13 18:09 input.txt -rw-r--r-- 1 ad ad 2 Apr 13 18:15 nums.txt -rw-r--r-- 1 ad ad 284 Apr 13 18:10 output.txt -rw-r--r-- 1 ad ad 313 Apr 13 18:13 sample.txt drwxrwxrwx 1 ad ad 512 Jun 10 2022 test -rwxr-xr-x 1 ad ad 200 Apr 13 18:17 test.sh
4.
Write a Bash script that executes another script named "test.sh" when executed.
Code:
#!/bin/bash
# Bash script to execute another script named "test.sh"
./test.sh
Save the file with a ".sh" extension, for example, "test1.sh".
Make the script executable by running the following command in the terminal:
chmod +x test1.sh
Ensure that there is a script named "test.sh" in the same directory as the script you just created, and it is executable.
To execute the script, navigate to the directory where the script is saved and run the following command:
./test1.sh
Output:
Current date and time: Wed Apr 17 08:12:40 IST 2014
5.
Write a Bash script that displays a message indicating the current user's username when executed.
Code:
#!/bin/bash
# Bash script to display the current user's username
echo "Current user's username: $(whoami)"
In the script above,
- echo "Current user's username: $(whoami)": This line prints a message indicating the current user's username. The $(whoami) command is used to retrieve the current user's username.
Save the file with a .sh extension, for example, test1.sh.
Make the script executable by running the following command in the terminal:
chmod +x test1.sh
To execute the script, navigate to the directory where the script is saved and run the following command:
./test1.sh
This will display the current user's username.
Output:
Current user's username: ad
6.
Write a Bash script that executes a command to list all files in the current directory when executed.
Code:
#!/bin/bash
# Bash script to list all files in the current directory
ls
In the script above,
- ls: This command lists all files and directories in the current directory.
Save the file with a .sh extension, for example, test1.sh.
Make the script executable by running the following command in the terminal:
chmod +x test1.sh
To execute the script, navigate to the directory where the script is saved and run the following command:
./test1.sh
This will list all files in the current directory.
Output:
abc.sh error.log file2.txt nums.txt sample.txt test1.sh document.txt file1.txt input.txt output.txt test test.sh
7.
Write a Bash script that executes a command to display the system's uptime when executed.
Code:
#!/bin/bash
# Bash script to display system uptime
uptime
In the script above,
- uptime: This command displays the system's uptime, showing how long the system has been running, the number of users currently logged in, and the system load averages for the past 1, 5, and 15 minutes.
Save the file with a .sh extension, for example, test1.sh.
Make the script executable by running the following command in the terminal:
chmod +x tes1.sh
To execute the script, navigate to the directory where the script is saved and run the following command:
./test1.sh
Output:
08:20:40 up 1:02, 0 users, load average: 0.52, 0.58, 0.59
8.
Write a Bash script that executes a command to display the available disk space when executed.
Code:
#!/bin/bash
# Bash script to display available disk space
df -h
In the script above,
- df -h: This command displays information about the available disk space on the system. The -h option is used to show the output in a human-readable format.
Save the file with a .sh extension, for example, disk_space.sh.
Make the script executable by running the following command in the terminal:
chmod +x disk_space.sh
To execute the script, navigate to the directory where the script is saved and run the following command:
./disk_space.sh
Output:
Filesystem Size Used Avail Use% Mounted on rootfs 101G 89G 12G 89% / root 101G 89G 12G 89% /root home 101G 89G 12G 89% /home data 101G 89G 12G 89% /data cache 101G 89G 12G 89% /cache mnt 101G 89G 12G 89% /mnt none 101G 89G 12G 89% /dev none 101G 89G 12G 89% /run none 101G 89G 12G 89% /run/lock none 101G 89G 12G 89% /run/shm none 101G 89G 12G 89% /run/user tmpfs 101G 89G 12G 89% /sys/fs/cgroup C:\ 101G 89G 12G 89% /mnt/c D:\ 245G 54G 191G 22% /mnt/d E:\ 245G 40G 205G 17% /mnt/e F:\ 245G 47G 198G 20% /mnt/f G:\ 199G 135G 65G 68% /mnt/g H:\ 151G 19G 133G 12% /mnt/h I:\ 196G 11G 185G 6% /mnt/i
9.
Write a Bash script that executes a command to display the system's memory usage when executed.
Code:
#!/bin/bash
# Bash script to display system memory usage
free -h
In the script above,
- free -h: This command displays information about the system's memory usage. The -h option shows output in human-readable format.
Save the file with a .sh extension, for example, memory_usage.sh.
Make the script executable by running the following command in the terminal:
chmod +x memory_usage.sh
To execute the script, navigate to the directory where the script is saved and run the following command:
./memory_usage.sh
Output:
total used free shared buff/cache available
Mem: 31G 8.0G 23G 17M 230M 23G
Swap: 12G 9.1M 12G
10.
Write a Bash script that executes a command to display the system's CPU usage when executed.
Code:
#!/bin/bash
# Bash script to display system CPU usage
top -bn1 | grep "Cpu(s)"
In the script above,
- top -bn1: This command displays information about the system's CPU usage. The -'b' option is used to run "top" in batch mode, and the '-n1' option specifies that "top" should only display one iteration of data.
- grep "Cpu(s)": This command filters the output of "top" to only show lines containing "Cpu(s)".
Save the file with a .sh extension, for example, cpu_usage.sh.
Make the script executable by running the following command in the terminal:
chmod +x cpu_usage.sh
To execute the script, navigate to the directory where the script is saved and run the following command:
./cpu_usage.sh
Output:
%Cpu(s): 6.9 us, 1.8 sy, 0.0 ni, 91.1 id, 0.0 wa, 0.1 hi, 0.0 si, 0.0 st
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