hello everybody,
here is my problem:
________________________________________
#include <stdio.h>
int main()
{
int i=10;
printf("value is %i",i);
return 0;
}
_________________________________________
when i compile and execute, nothing appears on screen!!
but if i replace the printf... (2 Replies)
I have a requirement to close all the file descriptors from 3 to 1024 for a particular application.
Right now, this is how I do it ..
for ( int i = 3 ; i <= 1024; ++i )
close(i);
The change I am looking at is, I want to do away with the number 1024 and replace it with a constant which... (4 Replies)
I'm not sure how to best explain what I'd like to do, so let me give an example. I used to work in a department that deals with internet security. This department had an "internal" website (only people in the building can get on it) and an "external" website (anyone in the world can get on it --... (1 Reply)
Dear all,
I have the files: xaa xab xac
and I try to paste them using $paste -d, xaa xab xac
I see:
output
3e-130
,6e-78
,5e-74
6e-124
,0,007
,0,026
2e-119
When I type: $ paste -d, xaa xab xac |less
I see:
output
3e-130^M,6e-78^M,5e-74
6e-124^M,0,007^M,0,026 (2 Replies)
I wonder string constant exists permanently or temporary.
For example,
printf("hello, world");
the function printf access to it is through a pointer. Does it mean storage is allocated for the string constant to exist permanently in memory? :confused: (4 Replies)
Dears,
Need you help with the below file manipulation. I want to split the file into 8 smaller files but without cutting/disturbing the entries (meaning every small file should start with a entry and end with an empty line). It will be helpful if you can provide a one liner command for this... (12 Replies)
Discussion started by: Kamesh G
12 Replies
LEARN ABOUT FREEBSD
crontab
CRONTAB(1) BSD General Commands Manual CRONTAB(1)NAME
crontab -- maintain crontab files for individual users (V3)
SYNOPSIS
crontab [-u user] file
crontab [-u user] { -l | -r | -e }
DESCRIPTION
The crontab utility is the program used to install, deinstall or list the tables used to drive the cron(8) daemon in Vixie Cron. Each user
can have their own crontab, and though these are files in /var, they are not intended to be edited directly.
If the allow file exists, then you must be listed therein in order to be allowed to use this command. If the allow file does not exist but
the deny file does exist, then you must not be listed in the deny file in order to use this command. If neither of these files exists, then
depending on site-dependent configuration parameters, only the super user will be allowed to use this command, or all users will be able to
use this command. The format of these files is one username per line, with no leading or trailing whitespace. Lines of other formats will
be ignored, and so can be used for comments.
The first form of this command is used to install a new crontab from some named file or standard input if the pseudo-filename '-' is given.
The following options are available:
-u Specify the name of the user whose crontab is to be tweaked. If this option is not given, crontab examines ``your'' crontab, i.e.,
the crontab of the person executing the command. Note that su(1) can confuse crontab and that if you are running inside of su(1) you
should always use the -u option for safety's sake.
-l Display the current crontab on standard output.
-r Remove the current crontab.
-e Edit the current crontab using the editor specified by the VISUAL or EDITOR environment variables. The specified editor must edit
the file in place; any editor that unlinks the file and recreates it cannot be used. After you exit from the editor, the modified
crontab will be installed automatically.
FILES
/var/cron/allow List of users allowed to use crontab
/var/cron/deny List of users prohibited from using crontab
/var/cron/tabs Directory for personal crontab files
DIAGNOSTICS
A fairly informative usage message appears if you run it with a bad command line.
SEE ALSO crontab(5), cron(8)STANDARDS
The crontab command conforms to IEEE Std 1003.2 (``POSIX.2'') with the exception that the dangerous variant of calling crontab without a file
name in the first form of the command is not allowed by this implementation. The pseudo-filename '-' must be specified to read from standard
input. The new command syntax differs from previous versions of Vixie Cron, as well as from the classic SVR3 syntax.
AUTHORS
Paul Vixie <paul@vix.com>
BSD May 13, 2010 BSD