Two processes are communicating through a pipe: A | B. A is writing data faster than B is reading it in. Is there any way to have A limit its writing rate to match B's reading rate?
AFAIK the pipe will get full, and will make A's writing block, waiting for B to read in more data. But is there a way to limit A's writing rate before the pipe fills up? (In a way it's like having a pipe with a really small capacity, but as far as I know pipe capacity is a constant compiled into the kernel.)
Code:
EXAMPLE FOR CLARIFICATION
Right now the command is printing out the following in 1-second intervals:
But with flow control it should print out (again in 1-second intervals):
...since "date" would block on the writing loop due to the slow reading loop.
I want to use ssh to execute a command and to wait endlessly to log everything (in file) that comes as a stream of the connected server. But unfortunately, in the manual its written "If command is specified, it is executed on the remote host instead of a login shell"
So what happens is that when I specify my command: ssh user@server "my_command"
It executed the command and the flow of execution returns to bash shell. So basically my session ends right after the command is executed. This happens only in case I specify command in the command line. If I login into ssh manually and then type "my_command", then the session doesn't end. I want the ssh not to exit, because after "my_command" executes, I want to capture everything in the session.
how to configure serial port RS-232 to use flow control? The reason is without flow control is is not working properly(dala loss etc.) Im trying to run it as it is just with setting the flow control flag and Im sending my data via loop-back on the rs-232 to GTK TERM on the same computer... but when I enable IXON/IXOFF in GTK TERM, my sending program cant even open the port...
I don't quite understand how pipes work in bash. I know that it takes an output from one command as the input in another command. What an output is I can get because it's what the command prints out to the screen. But how do I know what input a command will take? Here is an example I thought would work:
Which gem | rm Unfortunately it didn't. Which gem prints out "/usr/bin/gem" so that must be the output right? I thought that was given to rm so it would be "rm /usr/bin/gem" but I was wrong. How do I know what input a command takes?
When I give the command: winexe --interactive 0 --user <user>%<password> //<ip_address> 'cmd /C dir' I receive the message: ERROR: Cannot open control pipe - NT_STATUS_ACCESS_DENIED The source machine is a RedHat EL4 server. The target machine is a Windows XP Home SP3 pc. When I give the same command to another pc all works fine. The other pc is a Windows XP Prof SP3.
I understand that $! is the PID of a command. For example:
Code: #!/bin/bash myprogram & echo "PID of myprogram is $!"
I'd like to send the output of "myprogram" to both console and to a log file using the "tee" command but I also want to store the PID of "myprogam". Something like this:
Code: #!/bin/bash myprogram | tee ./logfile & echo "PID of myprogram is $!"
The problem is that $! is now the PID of "tee" rather than the PID of "myprogram".
I have script which does file locking via flock and then writing it's pid into that file. It perfectly works being run by hand in terminal, running under cron on Debian, but somehow fails being run under cron on Centos 5.6. Script part and straced outputs are below.
I move a page from a server in SuSe to Debian and this script was working well but when I move the page to a Debian base server it is sending in the logs the following message:
cat: write error: Broken pipe, referer: [URL]
The cgi does the following, read a db file plain text that repeat each 15 lines an information where to look the seraching info. if it is there sends to the output the 15 lines block. but it was not sending errors in suse distro, does anybody knows why the cat's line are sending "cat: write error: Broken pipe," if I am not writing or making a pipe with ">" to none file.
Now my script is able to start server, But I am still have some problem with my script. When the start server command is executed, the control does not pass the line and does not execute further of that line.what is the problem and how can I get smooth execution of the my script. My Script:
I've written a simple server in linux used fork to create a FIFO pipe.The server create two FIFO pipe.One for server read data from client and write data to client.Then another pipe for client read data from server and write data to server.When the server read data from a client used server-pipe and then write data to client.But ,if the client no read open the pipe,the server side write will be crashed because of a broken-pipe SIGPIPE. How to check whether the read side is opened?Or,how to catch the SIGPIPE,and then my server will still execute on,not crashed!!
I'm doing ping between 2 RH servers through a VPN site2site tunnel and in some times I got in the result pipe 2 and another pipe 3 as I mark it in blue color below.
e.g.
64 bytes from 192.168.1.10: icmp_seq=0 ttl=128 time=0.229 ms 64 bytes from 192.168.1.10: icmp_seq=1 ttl=128 time=0.287 ms 64 bytes from 192.168.1.10: icmp_seq=2 ttl=128 time=0.278 ms
[code]....
What's the difference between pipe 2 and pipe 3 and what's the meaning of it?
I had tried to control lynx by bash script. I can use bash script to let lynx open an url. After that, I can't do anymore. I don't understand how to move the cursor or fill some textbox in the webpage opened by linx in bash script.
I have a set of files to copy and decompress, and want to do these operations concurrently with a script.
Manually it would be something like:
Code:
The single & is intended to background the processes, while the && is intended to execute the gzip process if and only if the cp completes successfully.
My script is:
Code:
When I run it, bash gets angry with the following error:
2. for I in 1 2 3 4 5 6 7 8 9 10; do echo $I; done|
3. for I in $(seq 1 10); do echo $I; done|
4. for ((I=1; I <= 10 ; I++)); do echo $I; done
I have a script which uses the 1st form of for loop. I'm trying to modify it to use a variable instead of a static hard-coded value in the section that controls the looping.of the for loop.
I've tried all different ways of quoting and escaping the variable, and the problem is that the quoting chars and escape char are being translated and passed into the loop along with the value stored in the variable.
For example, to change the start value of 1 to whatever value I want passed in through a variable:
Change:
I have tried: {{$a}..10} and {`$a`..10}, to have the variable evaluated first.
I have tried using the eval() function.
I have tried single and double quotes and the backslash escape character.
Nothing I've tried works. It's probably a syntax error.
I want to set a key binding in bash for "history-search-backward" readline command to a combination of Control+some other key (I'm using 2 as an example), but I'm unable to do so. in fact, I'm unable to alter or add bindings to Control+key combinations.
After several tries my ~/.inputrc now looks like this
But it doesn't work and bind -p | grep "-2" gives nothing. If I try something without the control key:
I can search in the history by prssing the sequence C + - + 2.
bind -p gives control in C form, for example:
I've tried different formats in my inputrc:
But nothing works.
works if I press Escape followed by 2.
Setup: Fedora 11: Bash version 4.0.23(1) GNU Readline 5.2 (according to the man page)
I am starting an instance of mplayer from a bash script, opening an audio stream:
Code: mplayer [URL]
How do I do to control this mplayer instance from another script? I want to control volume and pause it from within the bash script. I know the commands for doing so from terminal, but once mplayer gets started from the script, how do I 'direct' the commands to that specific mplayer instance?
I am trying to encrypt a file on-the-fly, redirecting the output to a named pipe [fifo]. I SSH into my server and run the command:mcrypt -k key < file > named_pipethen from my laptop I try to scp it:$ scp me@server:~/dir/named_pipe d it says scp:users/home/me/dir/named_pipe: not a regular file
I'm on the command line, as the install for the proprietary ATI driver has failed. I'm following the instructions for troubleshooting here but the pipe "|" key is not working - a tilda "~" shows up when I press it.I'm wondering if this is because of the keyboard being set as UK instead of US? I did have to change this setting at the graphical login initally, whether from choosing this setting by mistake or the installer choosing it automatically when I chose English UK for the language.
We want to kill a process provided that only process name is given and we are to first find out the process id and then kill the process. Yes, in one go! That is, using pipe.
I have a text file containing the URL I wanted for mplayer to play. Currently, I play those in commend line using the following steps: 1)cat playlist 2)use mouse to highlight the link 3)type: mplayer then click both left/right mouse button
I was hoping if I can do this in comment line without mouse. I've tried the following without luck. (assume there's only 1 address in the text file) 1) cat playlist |mplayer 2) cat playlist |awk '{print $1}'| mplayer
i was thinking that is there a way to check data flow for viruses? i mean if i set up calm av in my internet sharing server could it detect anything in incoming and outgoing data ?!!
I am working on a build-test system of a set of codes. The system (large enough) is such that one shell script does some work and calls another shell script. This inturn calls a third shell script and so on. How to get the list of all such shell scripts according to the way they are called.? More like a shell script flow tree?
I have two Linux processes communicating via a nameless pipe. How can monitor the traffic in the pipe? How can I inject data into the pipe? I have root access and know the pipe inode.
I'm storing a list of strings in a file and would like to read the file and pipe each line returned to grep which in turn searches a directory for files containing the string.However this is not returning any output.
