Questions tagged [mkfifo]
The mkfifo tag has no usage guidance.
20
questions
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views
Adding 'Progress bar / counter' to a parallelised For Loop
I've been greatly inspired by this question: Parallelize a Bash FOR Loop to parallelise some tools I've written that involve very loooong while read loops (ie doing the same task / set of tasks ...
- 43
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1
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100
views
How to guarantee that that only a specific process reads from a named pipe?
Suppose that, at time (1), I create a named pipe using Python with the goal that eventually this Python process would write something to that named pipe. Why? Because, at time (2), there is another ...
- 143
3
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0
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311
views
How to pipe all output streams to another process?
Take the following Bash script 3-output-writer.sh:
echo A >&1
echo B >&2
echo C >&3
Of course when ran as . 3-output-writer.sh it gets the error 3: Bad file descriptor, because ...
2
votes
2
answers
43
views
Process in Pipe which Processes 256 bytes at a Time
I have a c program on a Cyclone 5 that does an FFT using the connected FPGA. This program currently takes 256 bytes from stdin and then process it gives the FFT results on stdout. I run it like this ...
- 123
2
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1
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116
views
Using tee and paste results in a deadlock
I am trying to redirect stdout of a command into two "branches" using tee for separate processing. Finally I need to merge results of both "branches" using paste. I came up with the following code for ...
- 21
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46
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Why don't named pipes respect the order at which readers were attached?
I have this test script:
#!/usr/bin/env bash
fif="foooz"; rm "$fif" ; mkfifo "$fif"
( cat "$fif" | cat && echo "1") &
sleep 0.1
( cat "$fif" | cat && echo "2") &
sleep 0....
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2
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2
answers
1k
views
How to write something to named pipe even if there are no readers
I have this little test script:
rm fooo | cat
mkfifo fooo
echo 'bar' > fooo # blocks here
echo 'done'
I am guessing that because there is nobody reading from the named pipe, that the write call ...
- 8,308
3
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1
answer
2k
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How to check for presence of named pipe on the file system [duplicate]
I tried using the -f flag to test if a named pipe is present
if [[ ! -f "$fifo" ]]; then
echo 'There should be a fifo.lock file in the dir.' > /dev/stderr
return 0;
fi
this check does not ...
user282164
0
votes
1
answer
124
views
Run program when/instead of writing to FIFO? [closed]
I have a program that writes data every second to a FIFO. Now I want to alter some of this data and write it to another FIFO.
What would be the best approach? Can I somehow pipe this directly to my ...
- 99
6
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1
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1k
views
Why doesn't mkfifo with a mode of 1755 grant read permissions and sticky bit to the user?
I'm creating a server and client situation where i want to create a pipe so they can communicate.
I created the pipe in the server code with
mkfifo("fifo",1755);:
1 for only user that created and ...
- 163
1
vote
1
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481
views
mkfifo to copy / move files
Is it possible to use mkfifo (named pipes) in Linux to copy files?
For example: I am extracting files from tar archive and I want them to be moved immediately to another location.
- 85
1
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2
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85
views
Two named PIPEs (PIPE_in/PIPE_out) connected with `tail -f` | String sent to PIPE_in doesn't reach PIPE_out
1.Create named PIPEs, pipe_in and pipe_out by running:
$ mkfifo pipe_in
$ mkfifo pipe_out
2.Connect pipe_in to pipe_out:
TERM0: $ tail -f pipe_in > pipe_out
3.Send string hello world! to ...
- 113
1
vote
1
answer
933
views
How to redirect stdin using mkfifo? [closed]
I searched on askubuntu, stackoverflow and I found this:
$ mkfifo fif.pipe
$ bash script.sh < fif.pipe
$ echo 'say HELLO' > fif.pipe (say command do something in the script)
But after $ bash ...
- 11
1
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0
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122
views
Where should I place named pipe files on RHEL7?
I done some quicky web searches to find out how to make a named pipe. It looks very straight forward I just need to execute as root: mkfifo filename, but what the best practice on where on the ...
- 2,113
2
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1
answer
1k
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How to create a bidirectional pipe in bash?
I have a program which reads from and writes to file descriptor 3. I want to let it write to fd 3, and be able to write to the other end of the pipe interactively which the program should read over ...
- 516
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1
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690
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Process substitution vs FIFO (created by `makefifo`)
As far as I know, process substitution in bash and FIFO (created by mkfifo) are both named pipes. They both seem viable solutions for communication between processes. I was wondering how to decide ...
- 90.6k
0
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1
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65
views
When does a command in a process substitution or FIFO start and finish running?
When does a command in a process substitution in bash start and finish running?
E.g.
when does command1 in command2 >(command1) start and finish running respectively?
when does command3 in ...
- 90.6k
2
votes
1
answer
6k
views
What is the purpose of using a FIFO vs a temporary file or a pipe?
From APUE
FIFOs can be used to duplicate an output stream in a series of shell
commands. This prevents writing the data to an intermediate disk
file (similar to using pipes to avoid intermediate ...
- 90.6k
5
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1
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How does this command work? mkfifo /tmp/f; cat /tmp/f | /bin/sh -i 2>&1 | nc -l 1234 > /tmp/f
Today I was reading the nc man page and stumbled on this command. I know that:
mkfifo /tmp/f is creating a named pipe at /tmp/f.
cat /tmp/f is printing whatever is written to that named pipe
and the ...
2
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1
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1k
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pipe data into process that's already started
Say I start a node.js process like so:
node script.js &
is there a way to pipe data into that process after it has started?
normally, we do this:
cat <file> | node script.js
but the ...
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