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first up, a linux newbie.
I made a typo and I have no idea what I've walked into, and documentation to no avail.
Screen shot:
running
man tail
unfortunately provided no help either.
what is this command doing?
Exit by using ctrl + C
The apostrophe ( ' ) has nothing to do with tail command. What it really does is it allows you to insert multi line text in commands.
$ echo 'hello
> world'
hello
world
Don't forget to add an apostrophe at end to enclose the text.
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Closed 4 years ago.
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After executing the command in the bash terminal :
printf 'A%.0s' {1..20}
A string consisting of twenty "A" characters will print to the terminal string. What is annoying is that the command prompt will follow directly behind the printed string, which clutters the terminal and looks unsightly, looks like this :
AAAAAAAAAAAAAAAAAAAAubuntu#ubuntu-VirtualBox:~/Desktop$
That looks terrible. Is it possible to get the command prompt :
"ubuntu#ubuntu-VirtualBox:~/Desktop$"
To appear below the printed sequence of characters?
Thank You.
Try bellow command and visit ( http://tpcg.io/5IFLfl ) to execute online :
printf "$(printf 'A%.0s' {1..20})\n"
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When I added !! in the end of echo command, it gave some output but I am unable to understand the output of the command. What does !! actually do in Linux?
!! Refer to the previous command. This is a synonym for `!-1'
Assuming your example is something like this:
echo hello!!
The answer depends on what shell you are using. Assuming bash merely because this is what I usually use:
From bash man page:
!! Refer to the previous command. This is a synonym for `!-1'.
This means that the command above will print hello followed by the previous command line from shell command history.
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I have just started learning the Linux system and I need some help to translate the following to English:
grep WARNING readme.txt
and
grep WARNING readme.txt > warnings.txt
This is a homework question that i have researched myself but having trouble learning exactly what it means.
thanks in advance.
Try making a file on your computer named readme.txt. Put some lines of text in there, and make sure that some lines say "WARNING" while other lines do not.
Then run your first command and observe its output.
Then run your second command and observe its output and observe what was written to warnings.txt.
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Closed 6 years ago.
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I have used a command called 'cat /etc/group' what does this command mean and do.Can you tell me what each part of the command does please use simple terms.
You can find the answer to your question explained better than any of us ever could with this command:
man cat
It prints to standard output the contents of the file at the location /etc/group
Ok so cat outputs the file, which (in your case) contains basic info about groups.
If you are interested in what are the groups just click here
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Closed 8 years ago.
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I have a strange issue.
There is file on which:
$ cat fp_id_led
1
$ echo 0 > fp_id_led
$ cat fp_id_led
1 <--- Still shows 1!
Also when I open the file in vim its just empty.
How can I flip that value in the file.
Probably the file is located not on a normal filesystem, but on a pseudo filesystem, like /proc?