How to Modify Printf With Last -10 Command In Bash?

8 minutes read

To modify printf with the last -10 command in bash, you can use the !! shortcut to access the previous command and then pipe the output to printf with the desired format. For example, you can use the following command to print the last -10 command in a specific format:

1
!! | tail -10 | printf "%s\n"


This will retrieve the last -10 command from the command history, extract only the last 10 lines using tail, and then print them using printf with the specified format. You can modify the printf format string to display the output in a different way based on your requirements.

Best Linux Books to Read in 2024

1
Linux Bible

Rating is 5 out of 5

Linux Bible

2
Practical Linux Forensics: A Guide for Digital Investigators

Rating is 4.9 out of 5

Practical Linux Forensics: A Guide for Digital Investigators

3
The Linux Command Line, 2nd Edition: A Complete Introduction

Rating is 4.8 out of 5

The Linux Command Line, 2nd Edition: A Complete Introduction

4
How Linux Works, 3rd Edition: What Every Superuser Should Know

Rating is 4.7 out of 5

How Linux Works, 3rd Edition: What Every Superuser Should Know

5
CompTIA Linux+ Certification All-in-One Exam Guide, Second Edition (Exam XK0-005)

Rating is 4.6 out of 5

CompTIA Linux+ Certification All-in-One Exam Guide, Second Edition (Exam XK0-005)

6
CompTIA Linux+ Study Guide: Exam XK0-005 (Sybex Study Guide)

Rating is 4.5 out of 5

CompTIA Linux+ Study Guide: Exam XK0-005 (Sybex Study Guide)


How to achieve specific formatting with last -10 and printf in bash?

To achieve specific formatting with last -10 output and printf in bash, you can use string formatting in the printf command to get the desired output. Here's an example of how you can achieve this:

1
2
3
4
5
6
# Get the last 10 lines from the last command output
last -10

# Use printf to format the output
printf "%-15s %-15s %-15s\n" "USERNAME" "LOGIN DATE" "LOGIN TIME"
last -10 | awk '{print $1,$5,$6}' | while read user date time; do printf "%-15s %-15s %-15s\n" "$user" "$date" "$time"; done


In this example, the last -10 command is used to get the last 10 lines of the last command output. The printf command is then used to format the output with specific formatting for the columns "USERNAME", "LOGIN DATE", and "LOGIN TIME". The awk command is used to extract the relevant columns from the output, and then printf command is used within a while loop to format and print each line of the output with the specified column widths.


What is the relationship between last -10 and printf output in bash?

In bash, the last -10 refers to the 10th most recent command that was executed in the terminal. On the other hand, printf is a command used to format and print data in the terminal.


There is no direct relationship between last -10 and printf output in bash. The output of printf or any other command will not be affected by the last -10 command. They are independent of each other and serve different purposes in bash scripting.


How to filter output based on last -10 with printf in bash?

You can use the tail command to filter the output based on the last 10 lines and then use printf to format the output. Here is an example:

1
2
# Display the last 10 lines of the output and format it using printf
your_command | tail -n 10 | while read line; do printf "%s\n" "$line"; done


Replace your_command with the actual command whose output you want to filter based on the last 10 lines. The tail -n 10 command will display only the last 10 lines of the output, and the printf "%s\n" "$line" command will format each line before printing it.


What is the impact of using last -10 on the output generated by printf in bash?

Using -10 in printf in bash will result in the output being right-aligned with a field width of 10 characters. This means that the output will be padded with spaces on the left side to make it a total of 10 characters wide. This can help to align the output in a more organized and readable way, especially when working with columns of data.


How to troubleshoot issues when using last -10 with printf in bash?

If you are experiencing issues when using the last -10 command in combination with printf in bash, here are some troubleshooting steps you can follow:

  1. Check the syntax of your command: Make sure you are using the correct syntax for both the last -10 command and the printf command. Ensure that you are properly formatting the output of last -10 before passing it to printf.
  2. Verify the output of last -10: Before piping the output of last -10 to printf, check the output of the last -10 command to ensure that it is in the expected format. This will help you identify any issues with the output that may be causing problems with printf.
  3. Test with a simpler command: If you are still experiencing issues, try using a simpler command with printf to see if the problem lies with the last -10 command. For example, you can try running last -1 and piping the output to printf to see if it works correctly.
  4. Check for errors or warnings: Look for any error messages or warnings that may be displayed when running the command. These messages can provide valuable information about what is going wrong and help you troubleshoot the issue.
  5. Try using a different command: If you are still unable to resolve the issue, consider using a different command or approach to achieve the desired result. There may be alternative ways to achieve the same outcome without using last -10 with printf.


By following these troubleshooting steps, you should be able to identify and resolve any issues you may encounter when using last -10 with printf in bash.

Facebook Twitter LinkedIn Telegram Whatsapp Pocket

Related Posts:

To create a table using a bash shell, you can use different techniques like using the printf command or a combination of commands. Here's a simple method using the printf command:Determine the number of rows and columns you want in your table. Use the prin...
To use any bash command in a bash function, you simply need to define the desired command within the function block. You can include any valid bash command or series of commands within the function. For example, you can create a function that checks for the ex...
To pass a seconds variable from bash to Perl, you can use command line arguments. In your bash script, you can call the Perl script and pass the seconds variable as an argument. For example:Bash script: #!/bin/bash seconds=60 perl script.pl $seconds Perl scri...
To check the status of the last command in Bash, you can use the special variable $?. Here is a brief explanation:Each time a command is executed in Bash, it returns an exit status. An exit status of 0 indicates success, while a non-zero exit status indicates ...
To write a basic Bash script, follow these steps:Open a text editor and create a new file with a .sh extension (e.g., script.sh).Start the script with a shebang, which tells the system to interpret the commands using Bash. Use "#!/bin/bash" at the begi...
To run a Laravel project from a bash file, you can create a bash script that will execute the necessary commands to start the Laravel server.First, navigate to the root directory of your Laravel project in your terminal. Then, create a new bash file with a .sh...