Chains the standard streams of a series of commands

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2answers
40 views

Merge lines in file together from regex to “lineify” multiline log log files

Stadard unix command line tools (grep, cut, sed etc.) all work one line at a time. And nearly always, this is great. However I am trying to parse some postgresql slow query logs. Each entry has some ...
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2answers
45 views

Using a file as an input to a script

Say I want to use the name of a file as input, and process it with a pre-made script in a certain directory. How do I do it? fileName < /folder1/scriptName is this the right format?
4
votes
1answer
79 views

uniq and bash for loop not writing to stdout before stdin closing (for one-line website visitor notification system)

I'm trying to trigger a beep on the PC speaker for every unique visitor of a website. After some brainstorming, it seemed to be possible with one line: for e in `ssh me@mymachine "tail -n 1 -f ...
2
votes
1answer
42 views

pipe mplayer output to other tool

I'm trying to play an online live stream via mplayer and pipe the audio from that stream to another tool. Playing the stream works fine: mplayer http://user:pass@192.168.0.1:8080/stream.flv But ...
2
votes
1answer
44 views

Syntax When Combining dd and pv

I am a linux newbie; so, sorry if this is obvious to you... sudo dd if=/dev/sda bs=64k | pv --size 1.5t | dd of=/dev/sdb Does the block size for dd go on the left side of this after the input as ...
2
votes
1answer
36 views

pipe speed benchmark with machine readable output

I'm looking for a tool similar to pv which is producing machine readable output. And i cant believe that nobody did it bevore... I looked at the manpages of pv, pipemeter, dd and cpipe but all these ...
2
votes
1answer
76 views

Is there a system call to bind a file descriptor directly into another?

A read() & write() loop would probably be as good as what I'm looking for, but nevertheless is anything like that around or is it impossible because of an obstacle I didn't envisage ? I'm curious
1
vote
1answer
100 views

Why doesn't this piped script work?

#!/bin/bash rm out mkfifo out nc -l 8080 < out | while read line do echo hello > out echo $line done If I browse to the IP of the machine this script is running on (using port ...
0
votes
1answer
29 views

Feeding audio from microphone live into python

Well, so I was reading about this raspberry pi tutorial that makes you play audio files from raspberry pi and stream them into a FM signal and something got me curious. You can stream .wav files, ...
0
votes
1answer
61 views

Combine the output of while loop into tar

I'm trying to create a script that mysqldumps all my databases, creating an individual .sql file for each database and combines the output into backup-DATE.tar.gz. I've gotten as far as being able to ...
-1
votes
1answer
129 views

Redirect a directory as input to a script and output to a file

I want to use a directory name as a parameter for a pre-made script. Then the output goes into a newly made file in the home directory. It involves pipe/redirection. How do I do that? read dir $dir ...
2
votes
0answers
33 views

BASH: Fifo troubles - seems selective about input

So I am having a problem with a BASH service in Debian 7 that I've been working on for quite a while and that randomly started having trouble with its fifo, or so it seems. It is based on kind of your ...
2
votes
0answers
35 views

Scripted write-then-read from Unix domain socket using socat

I have a simple server listening on a Unix domain socket (on a CentOS box in case that's important). When I send the command "DATE" to the socket it writes back a welcome message and then "APRIL 15 ...
2
votes
0answers
31 views

Close All Piped Commands if one close

I'm running at least 3 commands (with progs) using pipes. For example program1 bla bla | program2 blabla | program3 bla bla Is possible to close all programX PIDS automatically if at least one ...
2
votes
0answers
407 views

avconv/ffmpeg output through /dev/ttyAMA0

I tried to pipe streaming video from video4linux2 webcam connected to a Raspberry Pi through /dev/ttyAMA0 to a computer using an Arduino as a intermediary. First of all, is it possible? Because I was ...
2
votes
0answers
429 views

How to redirect and use the framebuffer?

I need to work on the framebuffer to record what is being rendered. Now, I figure out how to convert the framebuffer in an image, I'm currently unable to obtain a constant stream of data from the fb ...
1
vote
0answers
18 views

Correct/Efficient/Reliable way to import log file entries to a MySQL database?

I'd like to be able to query our server access log files to identify abuse patterns. Log files really aren't very queryable, and it would be fairly easy to do what I wanted if each hit was a row in a ...
1
vote
0answers
55 views

Verbose output in logfile and simple output on screen?

Let's say I have the following script: script.sh and i want the verbose output in a logfile and simple output on screen. Logfile should contain the csh -v script.sh output, and on the screen should ...
1
vote
0answers
364 views

Why does this pipeline get SIGTTIN?

When I run the command for i in *.log; do cat "$i" | sort; done | more, the pipeline gets a SIGTTIN signal and is stopped. bash$ for i in *.log; do cat "$i" | sort; done | more ### (one screenful of ...
1
vote
0answers
187 views

Automatically start named pipe reader on startup?

I'm trying to run a script with root access from PHP. I can't do that because Apache's user, www-data, don't have root access because of security reasons. To fix that, I was advised to use a named ...
0
votes
0answers
32 views

What to use instead of `buffer` for 1GB buffer?

buffer(1) seems to be old-ish and have hard-coded values preventing it to cache large amount of data. $ buffer -m 1G max_shmem 1 too low // it doesn't even understand gigabytes $ buffer -m 1000M ...
0
votes
0answers
44 views

Create tar file which consists of directories from another tar file

I have tar file with three directories, dir1, dir2 and dir3. Is there a way to extract dir2 and dir3 directories to create new tar file on the fly, without extracting the directories in temporary ...
-1
votes
0answers
34 views

How to merge these three task in a single command ( grep | sed | echo)

I am trying something where I parse out from the tags in a file then add back the HTML. I see everyone suggest not to do such with regEx (grep). but here it is grep -m 1 -oP ...