Skip to main content

Questions tagged [streams]

In computer networking, STREAMS is the native framework in Unix System V for implementing character devices.

Filter by
Sorted by
Tagged with
0 votes
0 answers
23 views

How to redirect after merge [duplicate]

I'm trying to get the exit code of an ls command with no other output. To do this I'm using ls /foo/bar/rak/zif/poo 2>&1 > /dev/null; echo $? But when I do this, I get a ls: cannot access /...
Yehuda's user avatar
  • 301
1 vote
1 answer
473 views

How to remove unneeded languages from video files using ffmpeg?

I have a number of video files (500+) with lots of audio and subtitle streams for languages that I don't need and would thus like to remove to conserve storage space. I tinkered around with ffmpeg, ...
KTorrentNG's user avatar
1 vote
2 answers
80 views

Is there a program that concatenates non-seekable streams (size not known in advance) and can separate them again?

I'm trying to concatenate multiple input files/streams into one stream (using the imaginary command stream-cat), pipe that stream into ssh and on the remote host separate it back into individual files/...
David Scherfgen's user avatar
13 votes
2 answers
2k views

Why is appending different streams to a file safe?

It's well known that redirecting standard output and error to the same file with cmd >out_err.txt 2>out_err.txt can lead to loss of data, as per the example below: work:/tmp$ touch file.txt work:...
Sweet Shell O'Mine's user avatar
0 votes
1 answer
819 views

Stream Audio over LAN, Linux -> Windows, Debian 8

Tried ping between computer's static IP's connected by router (General failure). Therefore UDP direct connection attempts went nowhere. Tried using ffplay and pulse to stream audio, but Debian 8 is ...
DaFuze's user avatar
  • 1
0 votes
1 answer
774 views

What would be the stream for file descriptor 3u?

I know that the stream for file descriptor 2u is stderr. However, I'm not sure what the stream for file descriptor 3u would be and why? Ultimately, what does 3u represent here?
user avatar
3 votes
0 answers
2k views

How to receive "v4l2-ctl --stream-to-host" stream from a machine on the same LAN on said host for use with, e.g., video conferencing software?

There is an example that streams a webcam to another computer by piping a V4L2 stream into netcat (v4l2-ctl --stream-to - | nc <host> <port>), and this works, but it feels redundant when ...
Alex's user avatar
  • 131
1 vote
1 answer
45 views

What exactly is a single "atom" in a standard stream in linux?

Conceptually, a stream is a sequence of "characters" or "atoms", i.e. a binary stream is a sequence of 0s and 1s. But in Linux standard streams, if I write a bash script that asks &...
user56834's user avatar
  • 135
2 votes
2 answers
614 views

Are there "non-standard" streams in Linux/Unix?

The so-called "standard streams" in Linux are stdin, stdout, and stderr. They must be called "standard" for a reason. Are there non-standard streams? Are those non-standard streams ...
user56834's user avatar
  • 135
1 vote
1 answer
231 views

What would need to be changed to create a new standard stream?

Hopefully this question isn't too abstract, it touches on a bunch of software throughout the stack. We all know about /dev/stdin, /dev/stdout, and /dev/stderr. What if I wanted to create a new ...
Alex Davies's user avatar
1 vote
1 answer
73 views

bash I/O redirection - how to append to stderr

I have a script that loops over some big collection of data and performs some lenghty operations. Then i need to sort | uniq -c its output. So to let it know that its alive, I print a dot every N ...
murison's user avatar
  • 163
1 vote
2 answers
1k views

Spawn a terminal and redirect its stdout to original process

I'm trying to spawn a new terminal, execute a few commands and pipe their output to stdin of the original process. A mwe of what I'm trying to do is the following bash one-liner: $ xterm -e sh -c &...
noibe's user avatar
  • 387
0 votes
1 answer
549 views

dd bs=X count=1 reads less than X bytes [duplicate]

I have dd from GNU coreutils 8.32. When I run { echo a; sleep 1; echo b; } | dd bs=4 count=1 then I get a 0+1 records in 0+1 records out 2 bytes copied, 2.0381e-05 s, 98.1 kB/s dd terminates during ...
Socowi's user avatar
  • 635
1 vote
1 answer
240 views

/dev/fd inconsistency

What explains the following inconsistency in the reported contents of /dev/fd? erhannis@mnode6:/dev/fd$ ll /dev/fd/ total 0 dr-x------ 2 erhannis erhannis 0 Jan 12 22:10 . dr-xr-xr-x 9 erhannis ...
Erhannis's user avatar
  • 239
3 votes
0 answers
722 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 ...
Sinus the Tentacular's user avatar
3 votes
1 answer
251 views

Piping curl http://cheat.sh/python to less is showing strange ESC[38;5;246m [duplicate]

I am kinda new to Linux. My base issue: I need to show the output of curl cheat.sh/python like a man or less page, so that I can easily scroll up and down. What have I tried: curl cheat.sh/python | ...
Midhunraj R Pillai's user avatar
0 votes
1 answer
8k views

tar (child): : Cannot open: Is a directory

I know thats a pretty dumb question but I didn't found this precise question on internet I try to tar -cvjf all the contents of a directory (/*) and directly redirect that to a file (> file) but ...
wxi's user avatar
  • 149
3 votes
1 answer
382 views

Is there any control character or hack to prevent simple command line tools from showing subsequent data?

I'ld like to hide ugly data from being shown by command line tools like cat (and maybe simple text editors too) which often get confused by binary data. For example a VT100 terminal sometimes gets ...
Pinke Helga's user avatar
0 votes
0 answers
29 views

Proper (working) way to return an int pointer through STREAMS?

I had been doing some work with an old SVR4 box with serial i/o when I found that the driver for the serial card did not support TIOCMGET through an ioctl call (e.g. ioctl(fd, TIOCMGET, &arg);). ...
mackbw's user avatar
  • 1
4 votes
2 answers
1k views

What are two caveats of line buffering in Unix?

A paragraph from APUE Chapter 5.4 about line buffer: Line buffered. In this case, the standard I/O library performs I/O when a newline character is encountered on input or output. This allows us ...
Focus's user avatar
  • 161
5 votes
2 answers
5k views

Reading partially downloaded gzip with an offset

Let's say that there is one huge db.sql.gz of size 100GB available https://example.com/db/backups/db.sql.gz and the server supports range requests. So instead of downloading the entire file, I ...
bravokeyl's user avatar
  • 153
1 vote
1 answer
2k views

Ffmpeg - youtube-dl

I have try to use ffmpeg to download youtube media in mp3. ffmpeg -i <url> -f mp3 output.mp3 It's working with other urls, but not with youtube-dl retrived youtube video urls. Ffmpeg returns ...
edadam's user avatar
  • 23
3 votes
2 answers
1k views

How to pass multiple files in one stream to process them pipe-like (without saving) on the receiving side?

I need to determine the filetype on an indeterminate number of base64-encoded filestreams coming from stdin (image files base64-encoded and cat'ed). A single file would simply be ... | base64 -d | ...
Nick Coleman's user avatar
1 vote
1 answer
41 views

Stream raminication with continuation if one branch breaks

Say I ramify a video stream to 2 ffplay processes cat video.mp4 | tee >(ffplay -i -) >(ffplay -i -) > /dev/null Now, if I kill one of the ffplay process, the stream is stopped which is not ...
user123456's user avatar
  • 5,088
3 votes
2 answers
616 views

Why were STREAMS marked obsolescent in POSIX.1-2008? [closed]

The POSIX.1-2008 XRAT rationale states that X/Open STREAMS may be removed from future versions of the standard, and that strictly conforming applications shouldn't use them, but it doesn't explain why....
osvein's user avatar
  • 199
1 vote
1 answer
2k views

piping text file to telnet over ssh

I would like to pipe a text file with commands to a telnet session I have open on a ssh client, Is this possible? an example: I have a text file cmds that contains commands like FirstFunction(A,B,C,...
stdcerr's user avatar
  • 2,079
2 votes
1 answer
312 views

How to store endless stream to file?

Let's have any stream of binary data (like /dev/random, /dev/zero, etc.). Let's have a file which size can be N at maximum. Let's the N is in order of gigabytes. Is there any elegant method/...
sharpener's user avatar
  • 135
4 votes
3 answers
2k views

How do pipes and infinite streams work?

I usually use command1 | command2 | command3 a lot in Linux but most of them are dealing with definite content. When I tried this with an infinite stream cat | sed '' | sed '' which hopefully ...
Nishant's user avatar
  • 643
5 votes
1 answer
2k views

Watch not showing subshell output

Why does the following not output "hello" line? watch bash -c 'echo hello' As this one? watch 'echo hello' I expected to have echo write to bash output directly and this to be read by watch and ...
sevo's user avatar
  • 1,237
24 votes
3 answers
29k views

How can I set up a "USB proxy" for /dev/ttyUSB0 over the network?

I have a device under test (DUT) and I measure its power usage the using a Power Analyzer Datalogger using the data from /dev/ttyUSB0. The problem is that the DUT is now remotely from the workstation ...
Eduard Florinescu's user avatar
23 votes
4 answers
17k views

How to use sed to manipulate continuously streaming output?

I am putting together a presentation for a non-technical audience. I have a program running in bash that outputs a continuous stream of values, a few of which are important. I would like to highlight ...
P Jones's user avatar
  • 343
3 votes
2 answers
2k views

Remove data from the STDIN stream buffer of another TTY session

I encountered a problem the other day while running multiple tty sessions in separate terminal windows. I was running a expensive disk access command and was waiting for it to return. Meanwhile I was ...
111---'s user avatar
  • 4,586
8 votes
2 answers
8k views

How I/O channels are implemented in Linux kernel?

stdin, stdout, stderr are some integers that index into a data structure which 'knows' which I/O channels are to be used for the process. I understand this data structure is unique to every process. ...
KawaiKx's user avatar
  • 465
0 votes
1 answer
3k views

How can I install STREAMS in Linux?

I searched on Google, but found nothing useful. I use SUSE now, how can I install LiS on my computer? I'm hoping for a download link.
Lidong Guo's user avatar