I've been using pipes and redirects for a long time and just realized that I don't know exactly how they are different. I just know that if you want to store the output in a file, then you use >. Otherwise most of the time you just use |. difference between pipes and redirects?
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recently I had been to interview where I had a question to be answered, that what are advantages and disadvantages when desiging an application in linux.
View 1 Replies View RelatedAlthough this is a basic stuff, but still i wonder.
Consider these two examples. code...
I wonder, why doesn't redirection work in first case? when to use redirect and when to use pipes? I have been Linux for a long time, but still this basic stuff baffles me.
File descriptors with pipes-Can someone help me with this three situations, what would happen?
a) a process open the same file twice and read through two file descriptors
b) a process does fork and both parent- and child-processes read parallell
c) two processes opens and read from same file.
has anyone seen this before, when running an ssh command as normal user via ssh i get results:
ssh picolo 'ls -d /var/sadm/pkg/* | egrep "Prod|Dev|UAT" |cut -d/ -f5;uname -r;grep -v "^#" /opt/Tivoli/lcf/dat/1/DMXAdaptiveFileSystem.dat'>>sshnotroot
and it creates file
more sshnotroot
Prod
5.10
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How to create and use named pipe on linux network.ie
client - my linux machine
server - my fren's linux machine
how to communicate between these two using named pipe created in C? do u have any similar code snippet written in C??
i got one server client application,its working fine on my machine.So i want enhance that code for networking.so help in this...
is there a way to make a symlink that redirects to the directory rather than acting as an alternate path? In other word, what I have now is:
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I want my pwd to be the hardlink pwd rather than the symlink pwd after changing my directory.
Is there already a program that reads multiple pipes or file descriptors and writes to the standard output (not splitting lines).Like cat, but reading all files simultaneously and preserving lines.It is needed to avoid coding of select/epoll loops or using multithreading in simple programs. Like "select loop for bash".
View 1 Replies View RelatedFor example, I have a script that writes the time to a pipe in /etc/pipe. It writes continuously in a while true loop. How long will the data in the pipe be available for reading? If I only decide to read the pipe a day later with cat /etc/pipe, will I get all the time values right from the time I started writing?
Conversely, what if my loop only wrote the time every 10 minutes. Will I be able to access everything a day later?
Finally, pretend my loop writes the time continuously (like my first example) and I read the pipe every 30 minutes. If my computer shuts down right before I read the pipe, will the pipe be empty when I reboot or will it hold all that data?
I'm looking for a programmatic way to run the equivalent of the below statement using SuSEfirewall2 and make it persistent:
iptables -t nat -A PREROUTING -s 192.168.1.4/32 -p udp --dport 514 -j REDIRECT --to-ports 51414
Yes I know I can add it to FW_REDIRECT in the config, but I really need to handle this on the CLI at run time (which the above statement does do), however... is there an iptables-save equivalent in SuSEfirewall2?
I am trying to install OpenSwan VPN but get the following [FAILED] errors. I also changed the redirects but it still reports them as failed?Quote:
[root@localhost /]# /sbin/sysctl -w net.ipv4.conf.all.accept_redirects=0
net.ipv4.conf.all.accept_redirects = 0
[root@localhost /]# /sbin/sysctl -w net.ipv4.conf.all.send_redirects=0
net.ipv4.conf.all.send_redirects = 0
[root@localhost /]# ipsec verify
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I'm trying to open a web page to automate some data checking, and I'm getting a "too many redirects" exception. I'm not experienced enough with Java to know what to try next, and would like some help.
I'll show the code for what I've tried, but first, details about the website:[URL].. The website is a series of aspx pages. Going to the above address in a browser gets you to "default.aspx"--a search page. You don't see the redirects (specifically to a Login.aspx page--which redirects back to default.aspx). I can get the search page with either Firefox or wget--and on the same computer that I'm writing the Java code on. So, Firefox and wget are doing something that my code isn't. Also, I'm not behind a proxy.
I've searched about the redirect exception, and one or two pages blame poor website development. That may be true, but I don't have any control over the website. So, fixing the website is not an option.
I did find this page where someone has the same issue. I used some code given in one of the responses to discover the default.aspx->Login.aspx->default.aspx redirection loop.
Much of my code was pulled from the Working with URLs and Working with Cookies tutorials from Oracle. I tried adding the cookie handler thinking that maybe Login.aspx was trying to create a session ID or some other connection-specific identifier. But either cookies are not the solution OR I just didn't code it the right way.
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After more searching, I'm 99% certain it's a cookie-handling issue. I added some more code (not included in the above) that examines the full response from the redirect to the Login.aspx page. The response includes a Set-Cookie header for "ASP.NET_SessionId". Now to find some code that will store and send the session ID.
I'm trying to redirect nc command output but I can't do it.
I have tried this:
And this:
But it seems doesn't work.
I have two sources of internet which I want to share and balance the load on. With one source it's easy: plug it into the wireless router and Bob's your uncle. But how would you handle two sources and get load balancing? A switch? Would that really share the load?
View 4 Replies View RelatedI need to find one RUNNING word in latest created logs.
and as soon as i will get RUNNING WORD , i have to execute another Unix Command.
I wrote following script code...
see these simple commands:
Code:
# dbus-monitor --system >> /data/eject.txt
This one works as expected ... dbus-monitor never terminates and whenever it outputs new lines, they are
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I have just installed opensuse and the codecs to replace windows on my laptop. This is my third day using open suse and some of the websites i try to open (amazon.co.uk, gmail.com and others) redirect to a chinese website called www.net.cn) This is the same with the firefox and opera browsers.
View 6 Replies View RelatedFor some reason my soundcard is recording every playback sound. This become apparent when I was trying to make a Skype call and the other people couldn't hear me. I checked my sound preferences and noted that the input was recording what they say (they could hear an echo). Also if I played back anything it would redirect to them. This has never happened to me and I've made a lot of calls in the past.
I tested with Audacity and it records fine, but when I play back the recording, it redirects to the input channel so it's not a problem with Skype. (my soundcard is a VIA VT1708B 8-Ch). Somewhere I read that the output of aplay -l is useful.
Here it is:
I use an external hdd (fat32 1tb usb) on my ps3 for music, movies and I'd like to create a folder containing a top 10 movies. Like a kind of playlist. Simple shortcuts wont do because my ps3 only recognizes avi , mp4 , etc. So I need to create a virtual file which redirects to its original. Without the ^shortcut^ taking any space.
View 2 Replies View RelatedStruggling to get my Linux server accept ICMP redirects not originating from default gateway. No problem to get it working if the redirects is originating from def gw.I know it's not a good solution security wise, but my network is so cluttered I'm forced to do so.
View 1 Replies View RelatedI have installed the new phpMyadmin3.4.1 on a server running Ubuntu 9.10 with apache and mysql. It runs on php5.2.10The apache config seems fine as the virtual directory that I configured works fine. http://<ip-of-server>/phpmyadminlink works. The home page is displayed. But when I enter the user name and password, instead of logging into the console, it again redirects me to the index page of the site. There are no errors displayed. I have checked that cookies on browser are enabled.The server is hosted on amazon web services, if that makes any difference
View 7 Replies View RelatedI have three machines networked to my desktop which run a bunch of simulations in parallel. As they're running, I connect to them via SSH and screen to keep an eye on the runs and look at the output. They stay usually connected for days at a time. The SSH servers and client are running Fedora 14. Yesterday one of my coworkers accidentally yanked the plug on one of the servers while it was running. When I powered it up again, I started getting some odd connection problems. I couldn't connect to it via SSH initially because I got the Remote Host Identification Changed (RSA host key changed) error. I deleted the key in .ssh/known_hosts, which allowed me to connect, but it denied my password. I then logged into that machine locally, restarted sshd, and removed .ssh/known_hosts again. Now I can log in via SSH without problems. However, the connection dies with a "Write failed: Broken pipe" error every few minutes (as opposed to the other two machines, which stay connected indefinitely).
So my questions are:
1.) why would a power loss affect the behavior of the SSH server?
2.) why do I keep getting broken pipes now?
Im new to fedora 11 and iptables, and i need to set the following set of instruction so VirtuaBox can accept request from lan, to the mailServer in the guest os, but after restart fedora i have to input it all again.How can it become permanent entry in iptables.
View 2 Replies View Relateddf -k
/dev/sda6 25396228 21249088 2836240 89% /export
21G used[code].....
The 3.4G is correct because we have removed all non essential file but free space reported by df is not consistent with the actual free space that should be there.
the difference between GLX and EGL?
View 1 Replies View Relatedwhat is the difference between C and gcc...
View 12 Replies View RelatedLast week in one of the Interview Dump Papers I read about NIS+. Anyone who can quick reference how the setting up NIS is different from NIS+.
View 1 Replies View Relatedwhat is the difference between a GUI and KDE..
View 5 Replies View RelatedI need to know the exact difference between SCP and SSH can somebody explain please as i am confused as both seem to do the same thing if so let me know what the difference is.
View 4 Replies View RelatedWhat is the difference between /dev/tty and /dev/pts ??
I google a lot but didn't understand......
Thanks in advance
