Linked Questions
24 questions linked to/from What is the difference between "Redirection" and "Pipe"?
28
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4
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What does the '|' (vertical bar) character mean in a Terminal command? [duplicate]
Example: In a Terminal command xdpyinfo | grep resolution (that I have taken from an answer),
does the | character mean that the xdpyinfo output shall be sent to the grep program input for printing a ...
- 1,417
5
votes
3
answers
634
views
What is | in terminal command [duplicate]
I've been trying to learn how to use apt-get in Ubuntu and I came across this command on a how to geek article
sudo dpkg –list | less
So this basically lets us look at a list of packages we have ...
- 221
3
votes
1
answer
2k
views
tee and output redirection [duplicate]
ls -l *.txt | wc -l | tee count.txt
ls -l *.txt | wc -l > tee count.txt
I am learning basic Unix commands. I thought those two commands mentioned would do the same thing, but they do not. Only the ...
- 775
-4
votes
1
answer
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Meaning of command1 | command2 is? [duplicate]
Please give the answer for what purpose we use this command only single '|'
Please tell me.
0
votes
1
answer
54
views
Why can I write to /dev/ttys010 using `>` but not `|` [duplicate]
I am trying to play around and understanding ttys.
In one terminal emulator window, the output of tty gives me
$ tty
/dev/ttys010
So I figured if I write to this device, the terminal window will show ...
634
votes
2
answers
1.3m
views
How to redirect stderr to a file [duplicate]
While using nohup to put a command to run in background some of content appear in terminal.
cp: error reading ‘/mnt/tt/file.txt’: Input/output error
cp: failed to extend ‘/mnt/tt/file.txt’: Input/...
- 7,204
320
votes
4
answers
250k
views
What's the difference between <<, <<< and < < in bash?
What's the difference between <<, <<< and < < in bash?
- 4,360
197
votes
3
answers
525k
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Command to append line to a text file without opening an editor
Assuming i have a line that i want to add to a file without opening an editor.
How could i append this line
alias list='ls -cl --group-directories-first'
to this file
config.fish
- 33.2k
89
votes
4
answers
178k
views
What's is the difference between ">" and ">>" in shell command?
Could someone explain to me the difference between > and >> when using shell commands?
Example:
ps -aux > log
ps -aux >> log
It seems the result is the same either way.
- 1,754
29
votes
6
answers
55k
views
How to get dialog box input directed to a variable?
I have been teaching myself bash scripting and have run into an issue. I have written a script to take input from the user, using the 'read' command, and make that input a variable to use later in the ...
- 313
49
votes
4
answers
57k
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What is the differences between &> and 2>&1
There are two forms of redirection the standard output and standard error into standard output. But which one is better? and why the &> is considered the perfect?
I can't find what is the ...
- 84.3k
38
votes
4
answers
17k
views
Why do shells call fork()?
When a process is started from a shell, why does the shell fork itself before executing the process?
For example, when the user inputs grep blabla foo, why can't the shell just call exec() on grep ...
- 1,309
29
votes
2
answers
6k
views
Do GUI based application execute shell commands in the background?
I have migrated to Ubuntu 16.04 just 2 days ago from Windows. I like the way we can customise the Unity Desktop. I am just playing around with the look and feel of the Desktop environment. Just like ...
- 606
27
votes
1
answer
91k
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What does echo with ">>" symbol do?
I've seen some command like
echo '* - nofile 65535' >> /etc/security/limits.conf
I know echo print something on the screen.
and limits.conf was a file in that /etc/security path.
But want ...
- 683
27
votes
1
answer
14k
views
What are directories, if everything on Linux is a file?
Very often beginners hear a phrase "Everything is a file on Linux/Unix". However, what are the directories then? How are they different from files?
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