i'm trying to redirect the output of a command to the input of the next command. not sure if i'm going about this the right way. an easy method would be just to store the output of the previous command in a file and redirect input to read that file, but i'm curious to see if this can be done without writing to any files.
View 9 RepliesI'm trying to write a program that will fork a series of FTP sessions. For each session, there should be separate input and output files associated with stdin and stdout/stderr.
I keep reading how I should be able to do that with dup2() in the child process before the execl(), but it's not working for me. Could someone please explain what I've done wrong? The program also has a 30-second sniper alarm for testing and killing of FTPs that go dormant for too long.
The code: (ftpmon.c)
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
[code]....
The output:
$ ftpmon
Connected to gila-crstest.gilacorp.com (172.16.20.8).
220 (vsFTPd 2.0.1)
ftp> waitpid(): Interrupted system call
Why am I getting the ftp> prompt? If the dup2() works, shouldn't it be taking input from my script and not my terminal? In stead, it does nothing, and winds up getting killed after 30 seconds. The log file is created, but it's empty after the run.
I'm working on an application used for backup/archiving. That can be archiving contents on block devices, tapes, as well as regular files. The application stores data in hard packed low redundancy heaps with multiple indexes pointing out uniquely stored, (shared), fractions in the heap.
And the application supports taking and reverting to snapshot of total storage on several computers running different OS, as well as simply taking on archiving of single files. It uses hamming code diversity to defeat the disk rot, instead of using raid arrays which has proven to become pretty much useless when the arrays climb over some terabytes in size. It is intended to be a distributed CMS (content management system) for a diversity of platforms, with focus on secure storage/archiving. i have a unix shell tool that acts like gzip, cat, dd etc in being able to pipe data between applications.
Example:
dd if=/dev/sda bs=1b | gzip -cq > my.sda.raw.gz
the tool can handle different files in a struct array, like:
Code:
enum FilesOpenStatusValue {
FileIsClosed = 0,
FileIsOpen,
[code]....
Is there a better way of getting the file name of the redirected file, (respecting the fact that there may not always exist such a thing as a file name for a redirection pipe).
Should i work with inodes instead, and then take a completely different approach when porting to non-unix platforms? Why isn't there a system call like get_filename(stdin); ?
If you have any input on this, or some questions, then please don't hesitate to post in this thread. To add some offtopic to the thread - Here is a performance tip: When doing data shuffling on streams one should avoid just using some arbitrary record length, (like 512 bytes). Use stat() to get the recommended block size in stat.st_blksize and use copy buffers of that size to get optimal throughput in your programs.
I want to run gsettings list-schemas (which return a list of about 100 names separated by spaces)and somehow direct each name one at a time as the input to this command:gsettings list-recursivelyI've tried it with awk, and standard | piping and also as a string variable strvar=$(gsettings list-schemas) and using the $strvar as the input butam missing something in between I'm sure like for - while or proper syntax of awk etc
View 3 Replies View RelatedI want to use the output of a previous command as a parameter to another command. For example: to know where "nice" is stored i typed: which nice output: /usr/bin/nice now the second command i typed is: ls -l /usr/bin/nice Is there a way to have a single command like: ls -l which nice ?
View 4 Replies View RelatedI have a starServer.sh command in a shell script along with a bunch of command. Th startServer.sh command prints out stuff on stdout and stays printing since the server is up. However eve though I want to start the server I want it to continue executing the commands after ./startServer.sh in the same flow.
View 4 Replies View RelatedThis seems so simple when doing it from command line but I'm not able to accomplish it inside a script. I am trying to put output of following command into a text file:
CMD= mysql -uroot -psecret -e 'SHOW SLAVE STATUS G;'
FIL=~/replication-`date +%F`.txt
MAILTEXT=~/mailtext.txt
touch $FIL
$CMD > $FIL
Where FIL is a variable that contains path of the file to which to output command. I am running this command in a shell script from where I want to email contents of $FIL as attachment using mutt. But I am always getting 0 byte file. Also if I examine in directory the file is of 0 byte length.
I would like to get the command and it's output redirected i have tried using the below but my syntax seems to be incorrect .
<<EOF
$(ls)
EOF
I need to achieve a particular effect using bash's redirection facilities.I know that I can redirect a file to some program's standard input:[user@host]$ application < file.txtThe thing is, I'd like to know can I regain control of this program's input after the file content's have been passed to it. In other words, I'd like to run a command similar to the above, and then, instead of the termination of the application, I'd want it to wait for further commands from standard input (keyboard).
As I write this question, it occured to me that I could probably write another application (or a script), that would at first write some data to standard output and then act as echo, like:[user@host]$ stdin_proxy.sh | applicationWould it work, and is there any better way to do so? There are a bunch of Googleable tutorials covering this issue, but they all amount to one advice - "reopen the stdin after the file contents have been read".
I'm writing a script to execute bash commands in the PHP CLI. I would like to suppress errors from bash and write my own error message if an error occurs. So far I have this (assuming log.txt doesn't exist!):
Code:
tac log.txt 2>/dev/null
Which works as expected, tac kicks up an error but the error is suppressed, but when I use this:
Code:
tac < log.txt 2>/dev/null
I get:
Code:
bash: log.txt: No such file or directory
The tac error is suppressed but bash still gives me a dirty error.
Allow me to submit that i did a mistake of not saving the work which i done in the past few months. i have used history command to see the previous commands. But trouble is that since i had worked a lot on gnome-terminal, only last 1000 commands are shown. Is it possible to see list of all the previous commands for all users. Also, sorry if this sounds absurd, but is it possible to save the details of a session onto a single file ? I not sure but when i had worked on vector Linux, i had used some command to save sessions at the terminal. Is there any analogous command in Ubuntu 10.04 also ?
View 2 Replies View RelatedFor example, when using bash you can use
Code:
to execute the previous command or
Code:
!<number> to execute the Nth command(use history to see the list). Or you can use
Code:
cd !-2:1
to cd into the value in the first field that was executed 2 commands ago Anyhow, say I run a command and the output is a path. Any way to cd and then some variable where OUTPUT of the previous command was stored? A variable that always stores the OUTPUT of the last command.
I have a command line server that logs to stdout, which I start along the lines of ./server > log.txt
What I want to do is limit the size of log.txt, without modifying the server.
I am assuming there must be some kind of tool already that lets me do this, something like where I can pass in my server, the output file and a size limit? If so, can anyone enlighten me?
Possible Duplicate: Navigate to previous directory in windows command prompt
Is there an equivalent of Linux's cd - (change to previous directory) in Windows?
I want to know the command, so that i can move back two days i.e. all the changes i made during the two day is rolled back .
View 5 Replies View RelatedWhen iwconfig is redirected thus Code: iwconfig >> wireless.txt things like Code: eth0 - Has no wireles extension are still outputted to the terminal (stdout)
View 2 Replies View RelatedI have a script where I want to redirect stdout to the terminal and also to a log file aswell as redirecting stderr to the same log file but not the terminal.I have the following code which I found on the net which redirects both stderr and stdout to a file and the logfile,
Code: if [ -p $PIPE1 ]
then
rm $PIPE1
[code]...
I was laughing about klackenfus's post with the ancient RH install, and then work has me dig up an old server that has been out of use for some time. It has some proprietary binaries installed that intentionally tries to hide files to prevent copying (and we are no longer paying for support or have install binaries), so a clean install is not preferable.
Basically it has been out of commission for so long, that the apt-get upgrade DL is larger than the /var partition (apt caches to /var/cache/apt/archives).
I can upgrade the bigger packages manually until I get under the threshold, but then I learn nothing new. So I'm curious if I can redirect the cache of apt to a specified folder either on the command line or via a config setting?
I know my way around MS Windows much better, but I just don't feel right trying to program something for Android on a Microsoft operating system. I am interested in Android programming so I followed the instructions on [URL] to install the environment on my computer...
I just installed the JDK, SDK, Eclipse successfully (or I assume):
* When I get to Step 4 where I'm supposed to run 'android' it will not run. I get the error message "android: command not found" (I am definitely in the right directory).
** When I double-click it in nautilus, it opens up in gedit. I can set the permissions in nautilus (through the properties - Allow executing file as a program) and get it to work,
My system:
Intel i7
Ubuntu 10.10 Maverick Meerkat
android-sdk-linux-x86
eclipse 3.6.2
I am using openSUSE 10.3.When I install software from tarball then to record time required I send output of date to beg.txt(when installation begins) and end.txt (when installation finishes).How can I append output of date to a file so I don't need two files?
View 4 Replies View RelatedI installed the Berkeley DB on the Ubuntu server and tried to access the dbxml from the command line and it returns command not found
path/to/dir/dbxml-2.5.16/install/bin$dbxml
-bash" dbxml: command not found
Can someone point me in the right direction
I want to be able to use Ctrl+R to have reverse-i search. Also if I press Shift+Up Arrow after typing the first few characters of a recently executed command then the shell should complete the command by finding the most recent commmand having the same first few characters.
View 1 Replies View RelatedBash's command history is great, especially it is useful when adding the history -a command to the COMMAND_PROMPT.However, I'm wondering if there is a way to log the commands to a file as soon as the Return key is pressed, e.g. before starting the command and not on completion of the command (using the COMMAND_PROMPT option would save the command once the prompt is there again).
I read about auditing programs like snoopy and session recorder like script but I thought they're already too complex for the simple question I have. I guess that deactivating that script logs all the output of the command would lead already in the right direction but isn't there a quicker way to solve that probelm?
When you run the following cp command in the BASH terminal, how does Linux know which files are the source and which are the destination when copying multiple files from one location to another?How does Linux know that the services, motd, fstab, and hosts files are the source and the /home/fred/my_dir is the destination?This question came up in a Linux class and I was not sure of the answer. I was thinking it is based on the source path entered ending with a file path and the destination being a directory, but was not sure.
View 4 Replies View RelatedPossible Duplicate: What does this cryptic bash command mean? Why this command crashes Linux? :(){ :|:& };:
View 4 Replies View RelatedUp until now I've been using plink to remotely compile a project I'm working on. But recently the administrator from the remote server updated the distribution and messed up some configurations. My project has a lot of scripts written for tc shell (tcsh), and now the default shell is bash. There is no way to change this. Another problem is that now I need to run newgrp to change my default user group.
So... to work around this problem I've changed my .bashrc to run newgrp and then tcsh. If I do a normal connection using SSH, everything works as expected, but when using plink, or SSH to remotely execute commands, the shell gets stuck on the newgrp command. I think it's because both applications need a return value from newgrp to send the command I need to execute. Remotely running scripts that call a shell also get stuck like newgrp (newgrp also opens a new shell and that's why it gets stuck) my .bashrc is as follows:
Code:
user_grp=`id -g`
if [ $user_grp != 4919 ]; then
newgrp new_group_id
else
[code]....
i want in the website they ask to enter some input.Code:echo -e "<p>Please Enter Year : c</p> "read Yearif i use this command it will ask the user to enter year in command. but what i want is they ask the user to enter year in web browser.
View 14 Replies View Relatedi want to disable the su command on a server so that users cant run the su command i removed the comment from the 3 and 5 line in /etc/pam.d/su file but it doesnt seem to work the file is shown below
#%PAM-1.0
auth sufficient pam_rootok.so
# Uncomment the following line to implicitly trust users in the "wheel" group.
[code]....
What's the command to delete bash command history?
View 4 Replies View RelatedI have a script which builds a project and then runs junit tests. However, if the build fails, the junit tests fail with the same error message.Therefore the command which runs the junit tests should only be executed if the build was successful.
View 3 Replies View Related