Read -s -n not working

10 More Discussions You Might Find Interesting

1. UNIX for Beginners Questions & Answers

Using read to assign value to bash variable not working

Hi, I am attempting to assign the output of the following command, to two bash variables, var1 and var2 using "read," but it doesn't seem to be working. # openstack hypervisor stats show | awk -F'|' 'NR==14{print $2,$3}' vcpus 92 # echo $? 0 # openstack hypervisor...

2. UNIX for Beginners Questions & Answers

Why this script is not working as 'expected' when doing ssh with while read ... really confused?

Hi, I have a script below that is running ssh <host> <command> on some servers. Below is more or less the script. I have to modify it somehow to get rid of the 'confidential' hostnames check_log.bash #!/bin/bash # myPID=$$ parse_log () { sub="parse_log" host=${1} ...

3. Shell Programming and Scripting

While read -a line not working in ksh

while read -a line; this is not working in ksh. what is the equivalent of this in ksh. read: -a: unknown option

4. Shell Programming and Scripting

[Solved] While read line and if statement not working

I'm looking for some help in figuring why my little bit of code will not process any entries other then the first one in my list. while read line ;do hostname=${line//\"} a=`ssh user@$hostname uptime;echo $?` if ];then dt=`date` touch...

5. Shell Programming and Scripting

Read statement not working

hello guys, i am having the below piece of code error () { echo"Press y /n" read ans case $ans in y) main;; n) exit esac } In the abve code, read statement is not working i.e not waiting for user to enter input. ,i tested exit status its 1. could anyone help me to do this ...

6. Shell Programming and Scripting

Read command not working as expected

I was trying to write a simple script which will read a text file and count the number of vowels in the file. My code is given below - #!/bin/bash file=$1 v=0 if then echo "$0 filename" exit 1 fi if then echo "$file not a file" exit 2 fi while read -n...

7. Shell Programming and Scripting

need to read lines in file and compare value in if not working

Hello, I have this file that sometime contains 0 lines and sometimes 1 or more. It's supposed to then put the result (could be 0 or 1 or 2 or more) into a variable. Then it's supposed to echo using an if else statement depending on the value of the variable. flagvar='wc -l $tempfile |...

8. Shell Programming and Scripting

While loop read line not working

Hi, I am trying to read a file line by line inside of a while loop. This while loop is part of a here document. while read line do ssh -t $2@$remotehost <<REMOTE ls path/to/dir > $path_to_dir while read line1 do echo "LINE --- $line" done...

9. Shell Programming and Scripting

Read statement not working in a script

I have a script consisting of certain functions whose input is a file at same location. In that file i have written the name of anothe file at same location. The third file contains a word which act as a function in the first script.Let me give an example i have a scrip file say 1.sh in which i am...

10. Shell Programming and Scripting

read statement not working in a function

Pls this is emergency.I have written a script which is taking input from another script. and the contents of my second script are acting as functions to my main script.Now the problem is that in one of the functions i want the script ececution to stop and start when user enters any character r...

LEARN ABOUT REDHAT

system

SYSTEM(3)						     Linux Programmer's Manual							 SYSTEM(3)

NAME

       system - execute a shell command

SYNOPSIS

       #include <stdlib.h>

       int system(const char *string);

DESCRIPTION

       system()  executes  a  command  specified in string by calling /bin/sh -c string, and returns after the command has been completed.  During
       execution of the command, SIGCHLD will be blocked, and SIGINT and SIGQUIT will be ignored.

RETURN VALUE

       The value returned is -1 on error (e.g. fork failed), and the return status of the command otherwise.  This latter return status is in  the
       format  specified  in wait(2).  Thus, the exit code of the command will be WEXITSTATUS(status).	In case /bin/sh could not be executed, the
       exit status will be that of a command that does exit(127).

       If the value of string is NULL, system() returns nonzero if the shell is available, and zero if not.

       system() does not affect the wait status of any other children.

CONFORMING TO

       ANSI C, POSIX.2, BSD 4.3

NOTES

       As mentioned, system() ignores SIGINT and SIGQUIT.  This may make programs that call it from a loop uninterruptable, unless they take  care
       themselves to check the exit status of the child. E.g.

	   while(something) {
	       int ret = system("foo");

	       if (WIFSIGNALED(ret) &&
		   (WTERMSIG(ret) == SIGINT || WTERMSIG(ret) == SIGQUIT))
		       break;
	   }

       Do  not	use  system()  from a program with suid or sgid privileges, because strange values for some environment variables might be used to
       subvert system integrity.  Use the exec(3) family of functions instead, but not execlp(3) or execvp(3).	system() will not, in  fact,  work
       properly  from  programs  with  suid  or  sgid  privileges  on systems on which /bin/sh is bash version 2, since bash 2 drops privileges on
       startup.  (Debian uses a modified bash which does not do this when invoked as sh.)

       The check for the availability of /bin/sh is not actually performed; it is always assumed to be available.  ISO C specifies the check,  but
       POSIX.2	specifies  that  the  return  shall always be non-zero, since a system without the shell is not conforming, and it is this that is
       implemented.

       It is possible for the shell command to return 127, so that code is not a sure indication that the execve() call failed.

SEE ALSO

       sh(1), signal(2), wait(2), exec(3)

								    2001-09-23								 SYSTEM(3)

Shell Programming and Scripting