Programming :: Effect Of Using Eval To Execute A Command As Opposed To Writing It On The Command-line?
Jun 18, 2010
Code: cmd='date | wc'
$cmd If this script is executed, an error is generated. The reason written was that "The execution fails because the pipe is not expanded and is passed to date as an argument".What is meant by expansion of pipe. When we execute date | wc on the command line, it goes fine.then | is not treated as an argument. Why?
I am trying to learn how to pass more than a one-command startup for gnome-terminal.
I will give an example of what I'm trying to do here:
Code: #! /bin/bash # #TODO write this for gnome and xterm USAGE=" ${0##*/} [-x] [-g] code....
However, running with the -g option to invoke gnome-terminal, I get a "There was an error creating the child process for this terminal" error.
This same error occurs if the gnome-terminal line is changed to
Code: gnome-terminal -e mcTerm
Is there any way to pass more than one command on to gnome-terminal? I have tried various single and double quoting senarios and in a final attempt, I abstracted to an exported function all to no avail. Perhaps even though gnome-term is better at many things than xterm, xterm trumps it in this instance.
Here is the block of code : (The red part is the code that doesn't work) The file is not created and see the output after the code. # i loop create environment structure and k loop create std procedure sub structure.
for i in TRAX2 TRAX BENCH PROD do eval mkdir $"acsayul02501_${i}" eval chmod 2770 $"acsayul02501_${i}"
Some time ago I installed LAMP in my server, but now I need to execute .php files from the command-line (in order to execute some manteinance scripts for mediawiki). Seems that the PHP files running in the server are run thru some kind of "module" in apache2. Can I tell apache2 to run a .php file in command-line mode using that php module? Or should I install a fresh copy of php-5? Won't that interfere with apache or mangle the system?
Is there a way to execute some command and then after the command completes utomatically reboot the system and then after the system reboots execute another command ? For example look at the sequence shown below(1) Execute command-1(2) After the command-1 in (1) is completed,reboot the system (3) Execute command-2(4) After execution of command-2 reboot the sytemIs there a way i can automate this process so that i need not reboot the system manually
i've gotten my fedora 12 to the point where i can run python3 scripts from command line and can call up python 2.6.2 idle with the command 'idle' from command line. what command will call up python3 (3.1.2 to be exact) idle?
I am running a java application on centos. For now I have a gsm modem connected via the the usb cable. Below is the message I get when I type the command dmesg | grep tty
serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A 00:0c: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A usb 2-2: pl2303 converter now attached to ttyUSB0
I would like to keep this simple and if possible use a piped command as opposed to an all out complex method.I have a script that does many things for me, and one of them builds a basic simple system report (I know about lshw, but this is for me to learn as well as be functional)
I would like to add another pipe to remove the"model name:" portion.I do not really want to use the store in a variable first solutions if I can help it.
I am executing a run command in a script after that i need to copy files into a directory which are the inputs for the run,on run a new shell is created and the remaining commands in the script does not execute,wot should i do to execute the remaining commands in the script??
i want to execute iptables command via php. i can run simple command as echo 'iptables -h'; but i can't run ipables -L and i create excutable file (firewall.sh). i can run it on console but not done on php.
I am trying to process a column separated data file, with a few bash command. For example, I have
Code:
file1 aaaa yes file2 aaaa no file3 bbbb yes
Let say I want to create new file with the output of first column and do something else with the output of 3rd column. Of course there are many ways to process this data file, but I wish to know by using awk, how could I do it. I'm trying:
Code:
awk '{system("touch $1")}' datafile
but the shell command will not able to get the awk '$1' output. How do I get this done ? And for another question, if the data file contains the variable name of a shell variable, how could I make use of it during a awk output ? For example I have a datafile1:
Code:
server1 yes server2 no
And in another server declaration data file, I got this datafile2:
Code:
server1=xxx1 server2=yyy1
And in my awk script, I want to achieve something like (the syntax is definitely wrong, just to demonstrate what I assume it will like):
This is weird. I have a shell script with no execute rights.$ chmod -x test.shThen I try$ test.shwhich does not work. (I have "." in PATH)When I do$ . test.shit works! I can run the script even though I have no execute rights. Why is that?Another question: If I have a shell script without a hash bang, I still can execute the shell script. Why? What does hash bang do? If there is no hash bang, why is the shell script run? What does the hash bang do
I have a big bash script ,its goal is to download movie one by one . But I often get into a problem: if this script is executed in cron,it often does not completely download the movie.I often find the movies it downloaded are several KB while the movie is actually 20MB.So I think it is because it did not wait for finishing one task ,and jump to download another.So I want to know ,is there a way to force the bash script to wait until one movie downloaded completely and then start to download another movie ?
I 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.
I am trying to write a perl script which will give an interactive session to a user to execute command on the server. I have written a small script to do this :
Code: !/usr/bin/perl -w use strict; use Net::SSH::Perl; my $host = '192.168.1.1'; my $username = 'user'; my $login_passwd = 'test123';
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,
which does not work on the invisible directories (why?). When I used ".*" as wildcard it changed all (visible) files including the parent directory (the one I was currently working in which is the "dot") . I can change the invisible directories owner and group using dophin but how is it done from the command line?
I'm building a script for my place of employment. The next step in it is checking what the user input was. Determining if they added a part in there or not. The script prompts for a hostname. Hostnames are localhost.localdomain. Now, I want the script to check to see if they put localdomain and if they did, not to add the domain to the /etc/sysconfig/network, but just what they entered. So say the user inputs:
I need to write a script that will take 1 command line argument. The argument will be a username. The script will determine if the user exists on the system and will print an error if it does not. If the user does exist it will determine if the user is currently logged in, if the user is not logged in it will determine the last time the user logged in and display the file in the users home directory that was most recently modified.
I am using an awk command to print a line from a cvs file.the awk command includes an if statement that filter the output-lets say i want to print all the lines that the price field is greater than 30.i have it working when i put the parameters myself.. but when i try to send them with vars it wont work..i am sending the sign of the if statement - can only be: == , < , >it looks like this:
I am wanting to write a program that runs a program or command-line. Is there are way of making a program that activates a command-line (for example executing 'ps -a -f' or '/home/shared/fah').
In addition to that, I want the program to do a 'ps -a -f' and put the results in a buff, how could I do this.