Not quite sure what is going on here, but there is a lot of duplication of code and the following should be functionally equilivent, without the duplicated code.
It's quite normal to use the "[" construct instead of test and tends to make things a little more readable.
Note if you dont wan't the error from ls to go to stderr you can redirect this to null like:
Hey Guys,
I am creating a bash script on my freeBSD box, the script should basically ask the user to enter a username and domain. The script will take this information and basically append alot of information to config files so the user can receive email from that domain and create a web site at... (1 Reply)
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
1. The problem statement, all variables and given/known data:
The object is to enter a number, then have another classmate guess the entered number.
2. Relevant commands,... (6 Replies)
hy guys,
I have perl script provided to me but i need to convert it into shell .Can you help me in this using sed shell command.
cat /etc/passwd |perl -ne '/^(\w+):\w+: (\w+)/ and print "$1, $2\n";' (1 Reply)
hi
i have been given the task of sorting some scripting issues , i first of all need to decifer the ones that are being used
is there anybody can do this for me :rolleyes: (4 Replies)
If there's anywhere to look this up, it would be just as helpful. I googled and really couldn't find anything relative to this.
ok... General Variables
1) When creating a script I made a file "prog1.sh" does it matter if the end is .sh or is this what has to be done like prog.bash or... (4 Replies)
Hello people, I am new to the forum and to scripting and I'm honored to be a part of the Forum :)
At the moment I'm learning to do basic scripting for school.
Now I got 2 assignments that I do not understand. The case scripting I have mastered a bit. But now I have an assingment to make with... (1 Reply)
hi all, i am very new to linux and am trying to create a basic script.
I would like the script to copy files from one directory into another, (e.g Script ~/my-documents/fileone ~/my-documents/filetwo)
Once all files have been copied, i'd like another script to run automatically and rename... (12 Replies)
Hello,
I am new to Linux and studying to become a Unix System Admin. I am taking a course in which I was practicing creating a bash script to ping a particular IP address. The script can be found below:
#/bin/bash
echo "Enter the IP address"
read ip
if
then
ping -c 1 $ip
if ;... (3 Replies)
I at the moment, making a simple bash script, capable of setting up an workspace for me, so i don't have to do it manually.. Problem is though i can't seem to provide the bash script any argument, without running into my error checks, checking for input...
Here is the code:
#!/bin/bash... (7 Replies)
Discussion started by: kidi
7 Replies
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)