Hallo everyone
I might just be being dumb, but I am using the BASH shell and cannot get the following script to work:
x=0
while
do
echo $x
x=´echo "$x + 1" | bc´
done
Can anybody help me out. I am just get a repeating output saying:
bc: command not found
0 + 1: command not... (5 Replies)
I'm just trying to make a script that runs in command line to echo each line in a text file. Everything i found on google is telling me to do it like this but when I run it it just echos removethese.txt and thats it. Anyone know what im doing wrong?
for i in removethese.txt; do echo $i; done
... (4 Replies)
i have the following process running in background:
when i give "ps -lef"
------------------------------------------------------------------------
user2
user1
user1
user3
user1
user4
user5
user4
user3
user4
user2
user1
user1
user3
user1
user4 (3 Replies)
i have a script called file2
#!/bin/ksh
i=0
while
do
echo $i >> result.txt
i=`expr $i + 1`
done
echo "***********************" >> result
------------------------------------------------------------------- (10 Replies)
I have what I believe is a simple programming question. I have a text file that looks like:
mol 1 G:\stereo01.hin
block text
...
...
...
endmol 1
However, I would like a file that repeats this entire block of text several times over. The lines of text in the middle remain the same for each... (2 Replies)
Hi expert,
I'm using csh
Code:
#!/bin/csh
set x = 0
set number = `awk '{array=$0} END {print array;}'`
i want to use for loop to store data to $number repeatly
untill x = 23
How to use c shell for loop? (2 Replies)
I need to chmod a bunch of files with a specific extension in one directory.
If I understand correctly first I would run ls command like this
ls -R | grep .mp3 > /tmp/list
once I have the output file I should be able to run a loop to chmod all the files in the list created.
This is where... (5 Replies)
Hello forum memebers.
can you correct the simple while program.
#! /bin/ksh
count=10
while
do
echo $count
count='expr$count-1'
done
I think it will print 10 to 1 numbers but it running for indefinite times. (2 Replies)
Does any body can help me with a loop in this example?
if
then
if
then
runner=$(grep "$1" "$2")
runne=$(grep "$1" "$3")
run=$(grep "$1" "$4")
fi
fi
#
# Message on screen... (3 Replies)
Dear experts,
I am writing a bash script. At some point of the program I need to have 'for' loop. For simplicity I tried with some other simple code. The format of the loop is given below.
k=51
m=55
for j in {$k..$m};do
w=$(($j+2))
z=$(($j+9))
echo "$w, $z"
done
But my... (4 Replies)
Discussion started by: vjramana
4 Replies
LEARN ABOUT SUSE
system
SYSTEM(3) Linux Programmer's Manual SYSTEM(3)NAME
system - execute a shell command
SYNOPSIS
#include <stdlib.h>
int system(const char *command);
DESCRIPTION
system() executes a command specified in command by calling /bin/sh -c command, 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(2) 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 command 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
C89, C99, POSIX.1-2001.
NOTES
If the _XOPEN_SOURCE feature test macro is defined, then the macros described in wait(2) (WEXITSTATUS(), etc.) are made available when
including <stdlib.h>.
As mentioned, system() ignores SIGINT and SIGQUIT. This may make programs that call it from a loop uninterruptible, 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 set-user-ID or set-group-ID 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 set-user-ID or set-group-ID 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.)
In versions of glibc before 2.1.3, the check for the availability of /bin/sh was not actually performed if command was NULL; instead it was
always assumed to be available, and system() always returned 1 in this case. Since glibc 2.1.3, this check is performed because, even
though POSIX.1-2001 requires a conforming implementation to provide a shell, that shell may not be available or executable if the calling
program has previously called chroot(2) (which is not specified by POSIX.1-2001).
It is possible for the shell command to return 127, so that code is not a sure indication that the execve(2) call failed.
SEE ALSO sh(1), signal(2), wait(2), exec(3)COLOPHON
This page is part of release 3.25 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
2004-12-20 SYSTEM(3)