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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How do I output a variable without changing if it has a newline or not in a shell script?

I have a shell script that takes input from another shell script. The stream gets piped in on stdin. I need to capture all the bytes of the stdin stream to a single variable in the shell script. ...
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2answers
47 views

Win7 Command Line piping

I want to know why in the command line prompt this happens. I have a script fileX.cmd which is one single line of text: @echo dir If I do C:\Users\Dogfood>fileX.cmd | cmd This will show all ...
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2answers
74 views

Use grep to find files and pipe/open to open them

How can I pipe files from grep to open all matching files? I've tried grep -li "type" * | open, but that does not work.
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1answer
54 views

Piping lines to repeat commands

If my grep operation returns a list of IDs like in the following, can I somehow feed/pipe each line to a commandline command's parameter?: 12345 84758 49549 .. Like for example with the above ...
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1answer
289 views

SoX pipe operations and data loss

When piping operations using SoX, I've noticed that files get shorter than they should: Works fine: sox -n -r 44100 silence.wav trim 0 1 sox --combine sequence silence.wav combined.wav soxi -D ...
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1answer
785 views

How to solve “Broken Pipe” error when using awk with head

I'm getting broken pipe errors from a command that does something like: ls -tr1 /a/path | awk -F '\n' -vpath=/prepend/path/ '{print path$1}' | head -n 50 Essentially I want to list (with absolute ...
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1answer
26 views

combining tail -f with less +F does not work

I am using ubuntu bash. I am trying to combine tail -f and less +F like below and nothing is coming out. tail -f long_running_log | less +F long_running_log is a log file constantly being written ...
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1answer
59 views

Batch to retrieve TFS version erroring in FOR /F where TFS attempts to PIPE to findstr

I have this partial batch, but it gives me an error (On 64 bit installations) SETLOCAL EnableDelayedExpansion REM Figure out what ProgramFiles Root we run the command SET ...
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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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1answer
299 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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1answer
164 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
515 views

OS X: log text from serial port

I have a text stream coming in on a USB-RS232 adapter. I want to pipe it to some Unix tools, to a file, whatever. What is the simplest way to do so? Does it really require third-party software? OS X ...
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276 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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176 views

Using pipes on ffmpeg has different behaviour than using files

I am using pipes to provide input and to send out output from FFmpeg The command I use is essentially ffmpeg -i pipe:0 -f flv pipe:1 I am using a Java program that basically provides an input ...
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0answers
1k views

'No such interface supported' when attempting to compress file through 7zip commandline

When I run the 7zip commandline: > echo foo | 7za a arc.7z -sifoo.txt Everything works as expected, but if I try to do: echo foo | 7za a arc.zip -sifoo.txt I get the following: ...
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30 views

Shell script for getting video fps

I'm trying using ffmpeg to get the fps of a video and save the value as a variable using this vid_fps=$(ffmpeg -i "$vid_file" 2>&1 | sed -n "s/.*, \(.*\) fp.*/\1/p") echo "$vid_fps" but ...
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8 views

How to store data from different netcat connections in separate files?

I need a server that should receive data streams, store them in files and send further. Each connection should create a file with corresponding timestamp in file name, then write to it. My solution: ...
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0answers
15 views

windows command line find file, untar

I want to untar a file I just downloaded in windows 7. I am in the directory, but there are too many files and the name is too long to simply type out. How would I do this in the command line? If this ...
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0answers
15 views

How can I run multiple sets of pipe-linked commands in parallel?

I want to run several sets of tasks connected by pipes in parallel like so: app1 "input_file_1" | app2 > "output_file_1" app1 "input_file_2" | app2 > "output_file_2" ... What is the cleanest ...
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21 views

Pipeline from <filename> to <filename> in Windows CMD?

Is there a way to do this without a temporary file? I've tried with tee but that failed. Test case: >echo "foo bar" > ex2.go >type ex2.go "foo bar" >type ex2.go > ex2.go >type ...
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40 views

How to pipe arguments into stdin?

I am trying to generate a private key using keytool command, but it asks me for many details like my key passphrase, my name and my organization details. I want to pass all the inputs in one command. ...
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18 views

How can I format the piped and refreshing output of multiple cmmands nicely?

I have a command line of multiple piped commands which executes beautifully in bash. For simplification: command1 | command2 | command3 Each command generates output while running, resetting the ...
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181 views

Pipe ffmpeg->ffmbc cut files after some length

I recently tried the following command: ffmpeg.exe -i "C:\Users\Dennis\git\cnn\CNN\watch\filea.mp4" -i "C:\Users\Dennis\git\cnn\CNN\watch\fileb.mp4" -filter_complex ...
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19 views

Merge two outputs into one in real time without scrambling them in linux

Is it possible to merge two real time outputs into one file without scrambling the new lines? What I want to do is something like cat <(/proc/kmsg) <(while true; do echo hello; sleep 1; done) ...
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56 views

Multiple grep command and show after line

I have this command grep -iE -A18 "$(date +"%Y-%m-%d").*error" * | grep -v -A18 'Movig to Error Queue' but the result shows me the 18 line after 'Moving to Error Queue' but I do not want that. I ...
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238 views

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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77 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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423 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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103 views

mutt colorizing piped messages

Viewing messages in mutt are colorized, but piping them through the less pager removes colorization. How do I preserve message colorization? I've tried: | less -R but colorization is stripped ...