I am trying to echo some value using awk, and for reading the file i am using cat command. If there no space in the file content then the following script result correctly.
console: # cat 1
one;two;three;
four;five;six;
[code]....
In case any space is there in the file 1 then i am facing the problem in the output value
console: # cat 1
o ne;two;three;
four;five;six;
[code]....
I'm confused about what "echo $0" in a shell actually return. Consider these tests:
Code:
[root@e11apvl151 ~]# # Login shell:
[root@e11apvl151 ~]# echo $0
-bash
[root@e11apvl151 ~]# # Starting a new shell
[root@e11apvl151 ~]# bash
[root@e11apvl151 ~]# echo $0
bash
[root@e11apvl151 ~]# screen
[root@e11apvl151 ~]# echo $0
/bin/bash
Depending on wether the shell is a login shell, a regular shell, or a screen utility, I get different results.
I am testing the serial ports on a Single Board Computer(SBC) running Linux kernel 2.6.29. I usually do this by connecting the serial port to another PC serial port, then doing "cat /dev/ttyS0" on PC and "echo hello > /dev/ttyS0" on the SBC. However in the current system, "echo hello > /dev/ttyS0" command does not return at all! Also no characters appear on the destination port. I am running the echo command as root. The system boot messages show that the serial port in indeed /dev/ttyS0.
View 2 Replies View RelatedI have always encountered this problem in ubuntu bash shell scripts that echo command in a function will be treated as a return value when used in a function. e.g.
[code]...
The output would simply be xyz. Hence the echo seems to function as a "return" command when used in a function with a return value.
What's the difference between PHP echo() and PHP print(), especially in the execution time?
View 6 Replies View RelatedI try to write script and echo two command at the same line .
echo "A"
echo "B"
How can I pipe above two command at the same line in text file . So, in the output text file , you can see below ? Code: A B not Code: A B
I am working on an epoll version of an echoserver that I am porting from a multithreaded version I wrote.What it should do: The server should get a connection from a client > say x client connected > print x message from said client. What it is doing: The server looks like it is only accepting one connection at a time, and any other clients are queued. When the queue is empty it looks like the program is aborting with a SIGABRT. EDIT:// fixed the program exiting in the close function. Still one client at a time
Code:
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
[Code]...
I am a student taking part in a comptition. We have a set of questions to complete within today. Can anyone please help me out with it. I have a custom written "echo" program in C, running on port number "1220" which echoes back the first 16 characters of whatever is given as the first command line argument. But somehow, my brother had got unauthorized remote root access. The program is given below. How did he do it? Please give the exploit code and explain how it works.
#include
#include
void echo(char* input) {
[code]....
I have a problem to use echo to display the content of a variable.
This is what I do:
Code:
#!/bin/bash
USAGE="Usage: name [OPTIONS] [DIRECTORIES]"
echo $USAGE
When I run this little script I get the following output:
Usage: name [OPTIONS] R
So I think that [DI might be some sort of escape sequence. But I do not know how to unescape it. Does anyone have a hint for me?
What is the difference between
$echo cat
$cat echo
I am trying to automate yum update of specific package on a remote machine. Essentially, the script executes, does a yum update, if not needed it would return echo result "update successful", if it needs the update and it installs it without error, it will return echo result "update successful", or if it fails the update it would echo "update failed". So far I have this:
[code]...
This is OK, but I NEED it to just return the final echo "Update successful". I can't have all the other lines. How can I do this?
I've read a bit about pseudo terminal but I still don't get it fully, I've found a really sweet article:
[URL]
I thought the two end tty and pty were acting like a pipe so while testing, I opened two terminals:
terminal1: cat /dev/ptyq9
terminal2: echo "test" > /dev/ttyq9
And it worked, terminal 1 printed: "test". But if the pipe is bi-directionnal ( as terminal were echoed back what user was typing), I was expecting to be able to go the other way around:
terminal1: cat /dev/ttyq9
terminal2: echo "test" > /dev/ptyq9
It does not work ! Echoing on pty just terminates the cat on pty. How is the "return" working them ?
how to echo an '-n' without a new line?
View 8 Replies View RelatedI can play audio in my alsa system and I can record. To keep things simple, I use arecord to record and aplay to play. So far so good. The problem is, I cannot hear what I am recording as I record it. Is there some way to get the input to be echoed to the output? I would optimally like to be able to do this before recording as well as during, so that I can check the levels, find the part to record on the tape, beforehand.
I have tried a test of my card: I had aplay running in one term and arecord running in another. They both ran fine and when I checked the just-recorded file, it was different audio from what I had been playing. This would indicate that the card is able to input and output at the same time, I think? I've done the usual googling as well as reading through URL... and I have done many passes of trial-and-error on my .asoundrc. The more I look at my .asoundrc, the more it looks like it should be doing what I want, but it is not.
My .asoundrc (which again, does works but does not echo audio input):
Code: Select all# pros: this allows playback and record. Playback of several
# programs at the same time works (their outputs are mixed
# together, mono and stereo mixed to stereo)
#
# cons: input is never echoed!
[code]....
I execute an application from a script file and redirect stdin to it from here-doc like this:
my_cli << HERE_DOC
enable
configure
10
exit
exit
HERE_DOC
This works as expected, but I don't see neither the input nor the app output. The application is an interactive prompt written in C. When I interact manually with it, I see the prompt itself and responses to my input, but when I execute the aforementioned script I see nothing. I would like it to print the input and the output as if a real user was typing. Do you know how to achieve that?
I have a process which logs output to log.txt. If I want to see the process's status in real-time, is there a way to echo that output to stdout instead of opening the log in a text editor and constantly reloading?
View 3 Replies View Relatedcheck the following program
/*a.c*/
int main()
[code]....
When I use rar e to extract a rar file, the request for entry of the password always says password will not be echoed. For longer passwords, this is difficult, since a single mistyped key will result in an error.
Does anyone know how I can use the rar command to extract and have the password echoed (appear on the screen as I type it)?
What does echo $$ give as output?
View 3 Replies View RelatedI'd like a function in my .bashrc file that would allow me to pass text to it and echo the text to a specified file. I know it's simple as "echo 'text' >> file," but ideally, I would want to alias the function so I execute something like:
Code:
user~ $ write 'this is a test' with "write" being the function, and 'this is a test' being echoed to the file. I hope I explained that well enough.
I would like to append text to a file. so i wrote in bashecho text >> file.confHowever it doesnt leave a new line. So i can only do this once. How do i add a new line?
View 2 Replies View RelatedI'm trying to create a shell script to take an argument and use it to name a terminal tab. So if the script's name is tabnm, tabnm "test" should rename the current tab "test"
This is my code:
#!/bin/sh
echo -ne "e]1;$1a"
but when i run it I get this output:
robin@icarus $ sh tabnm.sh test
-ne e]1;test
If I just run echo -ne "e]1;Testa" straight in the shell, the tab is renamed.
I'm a n00b in shell scripting,echo "$num $den $file" is the current formatI need 10 right padding for each term above in the above where $num & $den is of %d type, whereas $file is %s type.
View 2 Replies View RelatedIn a script, when I enter "echo $1" the first argument is outputted. When I enter:
a=1
echo "$$a"
The output is just "$1", not the first argument. If I enter:
a=1
b=$$a
echo $b
The output is still "$1" and not the first argument. How can I get echo to output the first argument without use "$1" directly?
I have ubuntu desktop 10.10. I wrote a simple script that I want to execute at system startup. The only problem I have (and one that I've been struggling with for the better part of the day) is that I don't see the outputs of the script during startup.
View 1 Replies View RelatedI was using a line device to record compact cassettes to digital (Linear PCM) then I transferred these files to the computer.Due to cassette print-through, there is audible, albeit weak, pre-echo. This is not caused by the recorder since I can hear them playing the cassettes on a deck.So. Does Audacity have a pre-echo removal function, or can a similar result be obtained by applying different effects? Or any 3rd-party plug-ins?
View 1 Replies View RelatedI want to prevent "^C" from echoing when Ctrl-C is pressed. I did "stty -echoctl" which some googling results suggested. Now it echos raw Ctrl-C characters instead of the string "^C". That's not any better since it displays some funny blocked hexadecimal in the terminal window.
View 8 Replies View RelatedI need to output a byte to LPT port. For this there's an option to program I/O ports directly (with ioperm & outb), but only if LPT port is a standard PC one (ports 0x378, 0x278, etc.). But i need a 'portable' way of doing this, i.e. which would also work on such interfaces as USB2LPT. I guess these adaptors will also have /dev/lp[0-9]* interface (am i right?). Here's what i get currently:$ echo 1 > /dev/lp0^CI.e. i have to use Ctrl+C because 'echo' never exits. When i had a printer connected to LPT, this did work
View 4 Replies View RelatedIs it possible to echo the arrow keys (up, down, left, right) in bash?
View 4 Replies View RelatedBelow is the shell script that I am writing to beep an alert but listen to nothing.
Code:
#!/bin/bash
echo Listen to the alert!
echo -e "a"
echo listened ?