Pipes or named pipes are a feature of the POSIX standard that allow separate processes to communicate with each other without having been designed explicitly to work together.

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error with upstart script

Further to my last question, I'm now using logger. I have the following upstart configuration start on runlevel [2345] stop on runlevel [06] respawn pre-start script exec 2>&1 > ...
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2answers
261 views

Pipe core dumps from script

I am making a testing script to compile (via make) and run a bunch of tests. I have a series of cat, grep and sed commands that organizes the results of all the tests nicely, however core-dumps are ...
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2answers
899 views

How do I pipe output to date -d “value”?

I have a date like "2014-01-30 05:04:27 GMT", and if I run date -d "2014-01-30 05:04:27 GMT", the output is in my server's timezone ("Thu Jan 30 16:04:27 EST 2014"). With the use of grep and cut, I ...
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1answer
125 views

debian keyboard key pipe not working , giving # instead.?

I have been using virtual box Debian and am unable to use the pipe key on the keyboard(hp -British) .the pipe key gives "# " instead and "# key" gives "pound sign"?. please help | gives # # ...
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496 views

How to unrar the STDIN?

What I have tried: cat archive.rar | unrar x - cat archive.rar | unrar x /dev/stdin cat archive.rar | 7z x - cat archive.rar | 7z x -si cat archive.rar | 7z l -si The unrar doesn't recognise the - ...
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2answers
914 views

How do you use PIPESTATUS, tee and /bin/sh together?

When I run curl | tee test.txt; echo ${PIPESTATUS[0]} I correctly see curl: try 'curl --help' or 'curl --manual' for more information 2 But when I try to run exactly same command using ...
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1answer
1k views

Add custom time to video frames using ffmpeg

I am using ffmpeg to encode raw pixels data (bgr32) into a video file. Pixels data is being sent from java application to ffmpeg stdin pipe. I am looking for a way to add a timestamp overlay to each ...
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75 views

how do you monitor the progress of a command line program?

We have some custom command line programs at our Windows shop. These commands are scheduled to run (from within bat files) at regular intervals using the Task Scheduler. Our tasks pull data from ...
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1answer
62 views

Can one redirect too much data?

I am working on a Linux system that runs on Kernel 3.2.0. On this system I wrote a program that in the end will generate roughly 50GB of data that it then would send to stdout. This output I want ...
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0answers
264 views

pipe unlimited curl stdout into chunked files

I've got an HTTP-endpoint that serves an unlimited stream of events. Now I'd like to record that stream using curl, but splitting the recorded files at the same time - preferably based on the line ...
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2answers
611 views

How to redirect a part of stderr and stdout to /dev/null

My program outputs to stderr and stdout. I want to grep for "pattern" either in stderr and stdout. And I want the rest to be sent to /dev/null. If I pipe after redirect stderr : ./prog 2>/dev/null ...
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2answers
356 views

PHP output piped to 'less' is requiring <enter> after every command

Piping PHP output to the linux 'less' command causes 'less' to really act up. (CentOS 6.2, didn't happen with CentOS 5.) When I pipe output from php into 'less', it requires the enter key be pressed ...
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404 views

mysqldump to local mysql database through ssh

This command: ssh bruchowski@www.example.com 'mysqldump -u bruchowski -p dbname' > mysql -u root dbname Produces this error: mysqldump: Got error: 1045: Access denied for user ...
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1answer
79 views

Linux - Output to Folder that Yet Exists (in one command)

Is it possible to achieve this in one command without requiring a script: echo "test" > /folder/that/does/not/exist/newFile.txt
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1answer
61 views

How many ways does Unix feign files?

I know Unix filesystem sometimes has things that appear to be files but are not actually files. The files in dev actually point to devices. Its also possible to created named pipes which also appear ...
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1answer
325 views

Programs detecting pipe on its output to disable coloration

Some programs have a colored output (such as grep or emerge on my gentoo system), but if their output is piped, into less for example or into a file, the colored output is disabled. Yet, I know less ...
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2answers
78 views

Sort files with grep

I have a few hundreds of output files, of which some contain error messages. Lets say I want to automatically put all files containing the string "ERROR_1" in a "subfolder_1", and the rest in a second ...
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3answers
764 views

linux tar -T - does not work on the fly

I found some problem with linux gnu tar. wheh I use option -T - (for file list from stdin) or -T named_pipe_file , this desn't work on the fly. for example, simple interactive script: while ...
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1answer
457 views

How can I pipe the output of *all* entered shell commands into another? (e.g. pipe everything into 'lolcat')

Good Afternoon, (OS X user) I am specifically trying to pipe the output of every shell command I type into the ruby gem 'lolcat' (which makes the output to the terminal rainbow colored). Is there a ...
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1answer
290 views

Why does echo work through pipe but not cat with msmtp?

This works: echo "yada yada" | msmtp my@mail.com but not this: cat yadayada.txt | msmtp my@mail.com which delivers the email with empty content. Why does echo work through pipe but not ...
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2answers
1k views

Using Piping with cat and less to concatenate 2 files

I'm fairly new to Unix commands and I just have a simple question. One exercise I'm working on wants me to use piping along with cat and less to concatenate 2 directories (in this case /etc/passwd ...
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1k views

tar piped to curl: This does not look like a tar archive

curl -L http://download.transmissionbt.com/files/transmission-2.80.tar.xz -s -o - | tar -xf - The error: tar: This does not look like a tar archive tar: Skipping to next header tar: Exiting with ...
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1answer
192 views

Having trouble piping output of dscl -list to -dscl read using xargs

I'm trying to get every user using dscl and reading each of their records using xargs and dscl. I'm not sure what I'm doing wrong, though, because I would expect this command to take each line of ...
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3answers
296 views

Pipe with ls command

When I want to know if a command is a link or not, I do like following. $ which locate /usr/bin/locate $ ls -l /usr/bin/locate lrwxrwxrwx 1 root root 24 5月 3 2012 /usr/bin/locate -> ...
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1answer
598 views

Running pdfcrack to include special characters in charset

I'm trying to recover a password from a PDF file using pdfcrack. I want to change the charset to include special characters. Can I use some kind of i/o redirect to feed the contents of a a similiar ...
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1answer
35 views

How do I save from VI to a pipe?

I've seen lots of ways to redirect input from stdin to VI, but I'd like to redirect VI to save to a pipe rather than a file. For example, I'd like to pipe VI's entire pipe buffer to another text ...
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1answer
414 views

Streaming log file contents (piping)

I am trying to understand how piping works and am stuck at this point. A log file is being streamed and its output is being piped to pigz. What I am trying to do is, redirect the pigz content to a ...
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1answer
268 views

Why the here-strings in bash are slower than piping the input to a command?

I compared the execution time for unix here-strings and pipe data input to bc: pipe time for i in {1..1000} do echo "sqrt(5.09)" | bc -q > /dev/null done real 0m3.584s user ...
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1answer
2k views

Pipe VLC output to ffplay?

I have a (broken) PC, where VLC plays videos on only the left half the screen, which seems related to OpenGL/drivers (see here). On the other hand, ffplay doesn't have the half-window problem, but can ...
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3answers
510 views

How to print out all non-hidden files recursively in a dir using lpr

find . -type f | grep -v '/\.' lists out all non-hidden files in the current dir recursively. Example of this command given the following file tree . ├── css │   ├── base.css │   └── main.css ├── ...
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946 views

Why is xargs necessary?

Suppose I want to remove all files in a directory except for one named "notes.txt". I would do this with the pipeline, ls | grep -v "notes.txt" | xargs rm. Why do I need xargs if the output of the ...
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1answer
158 views

redirect awk information to stdout

I am trying to gather information for CPU use for all the processors in a text file. mpstat -P ALL -u 1 | awk '{print $4}' > cpu.txt && mptat -P ALL -u 1 | awk '{print $4}' | tee cpu.txt ...
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1answer
746 views

Flushing a named pipe

I am using the following to redirect output from my script to both terminal and log file while appending date to every line that goes to the log file: NPIPE=/tmp/$$_$RANDOM.tmp mknod $NPIPE p tee ...
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2answers
212 views

When did the windows command line get the pipe (|)? [closed]

I freely admit I have very little experience with the Windows cli but I seem to recall that DOS had no pipe (or redirect for that matter, but I may well be wrong, its been a while). I have seen some ...
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3answers
3k views

How to pipe data over tcp from the command line?

I would like to pipe data from one machine in the command line to another machine over tcp. I guess I could write a socket server but this must already be implemented. For example I could use it to xz ...
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1answer
429 views

grep with colored output returns several empty lines

I have strange issue with grep (2.12-2, debian testing). In some situations when I do something like this: grep -rni '."spacer">.' . grep return me several empty lines: If I add --color=none ...
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1answer
298 views

Shell script detecting errors from command called by script

I am calling applications from my shell script, which performs a number of important steps in sequence, one step being below: for database in $( echo 'show databases;' | mysql ...
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2answers
94 views

Finding folders only

My harddrive is in a mess, so I decided to do a cleanup. As a part of this, I want to merge all folders containing music into one. What I want to do is, look for any *.mp3's and *.aac's on my drive ...
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152 views

Dynamic terminal title: show server load status at X second interval

When I have a bunch of terminals open in my WM it would be nice if terminal window titles reflected current user and host (easy) along with dynamic server load details, updated at some interval ...
6
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1answer
2k views

Pipe not working in cmd.exe on Windows 7

I have started seeing some very strange issues with the pipe command not working on Windows 7 64-bit on my machine. Commands like this: echo test | more used to work without a problem, but now ...
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1answer
519 views

Reading the same stdin with two commands in bash

I would like to pipe an output of to two separate commands <2,3> in bash. What is the best way of doing this? At the moment, I have following script: command source > output command2 output ...
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2answers
228 views

Windows Vista piping dir output into attrib command

I had a virus or something on my computer that set the attributes for all the folders in the root of my external drive to system and hidden, and created shortcuts to them. I am now trying to remove ...
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1answer
341 views

Alias defined in .bashrc not working after pipe

I'm stuck with the following problem. I've defined an alias in .bashrc (and .bash_profile): alias echo2="echo" This works well: $ echo2 "test" test However, if I try to use it after a redirect, ...
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1answer
2k views

How to redirect multiple bash commands to a variable AND screen?

I would like to capture a subshell's output in a variable and print it in the terminal screen simultaneously. Is it possible to do this by assigning the subshell to a variable and piping stdout and ...
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1answer
813 views

piping output from curl to rpm2cpio

I download alot of srpms to rummage through, I used to go through a long winded approach, root@server$ curl rpm -o file.rpm root@server$ rpm2cpio file.rpm | cpio -id but that leaves behind an ugly ...
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3answers
147 views

Transparent usage of temporary files as means of piping [closed]

As many of us are surely aware, it's always a good idea to make your program accept stdin input. Very many programs do allow that *nix environments. This lets us do cool things like piping echo "foo" ...
5
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1answer
355 views

cat-ing a file to a unix pipe causes Matlab to freeze

I've created a named pipe on Debian using mkfifo pipe.in. I want to write to this pipe from Matlab. To do this, I use the following matlab command: unix( 'cat <myfile> > pipe.in' ) ...
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3answers
332 views

How do I make a bash alias that outputs file names in a format I can pipe to vim?

When rebasing with git, I'm interested to open the files that have merge conflicts. I can do this with: vi `git diff --name-status --diff-filter=U | awk '{print $2}'` but if I alias that: alias ...
4
votes
1answer
1k views

Rendering HTML from a pipe

I would like to be able to generate HTML then pipe it to a program which will render it, something like this: for i in 1 2 3 do for j in a b c do echo "<table ...
3
votes
1answer
249 views

Redirect stdout to multiple programs

I'm doing some stream processing of some quite substantial files-- I was wondering if there was a way to split stdout in order to pipe to multiple programs. What I'd like to do is something like this: ...