at

apche个各种命令是at命令的应用

[root@s205 root]# at 1:08pm
warning: commands will be executed using (in order) a) $SHELL b) login shell c)
/bin/sh
at> ls
at> pwd
at> mkdir 111
at> <EOT>
job 1 at 2007-04-26 13:08
[root@s205 root]# cat /var/spool/mail/root
From [e-mail]  Thu Apr 26 13:08:01 2007
Return-Path: <[e-mail]>
Received: from s205.localdomain ([127.0.0.1])
        by s205.localdomain (8.12.8/8.12.8) with ESMTP id l3QH81N0003643
        for <[e-mail]>; Thu, 26 Apr 2007 13:08:01 -0400
Received: (from root@localhost)
        by s205.localdomain (8.12.8/8.12.8/Submit) id l3QH81VN003638
        for root; Thu, 26 Apr 2007 13:08:01 -0400
Date: Thu, 26 Apr 2007 13:08:01 -0400
From: root <[e-mail]>
Message-Id: <[e-mail]>
Subject: Output from your job        1
To: [e-mail]
 
111
1.sxw
1.txt
2.sxw
2.txt
3.txt
444.txt
445.txt
555
555~
anaconda-ks.cfg
example
example~
gong.tar
http
httpd-2.2.3-1.i386.rpm
install.log
install.log.syslog
?? Microsoft Word ??.doc
mysql
mysql-4.0.26.tar.gz
MySQL-client-5.1.7-0.i386.rpm
MySQL-server-5.1.7-0.i386.rpm
????????????????.part1.rar
????????????????.part2.rar
putty-0.59-installer.exe
????.rar
s03
s44
s444.txt
ssh??.doc
tmp
xplns_related
λ??-064100713.rar
/root
mkdir: cannot create directory `111': File exists
[root@s205 root]# at -f job 13:13
warning: commands will be executed using (in order) a) $SHELL b) login shell c)
/bin/sh
job 2 at 2007-04-26 13:13
[root@s205 root]# cat /var/spool/mail/root
From [e-mail]  Thu Apr 26 13:08:01 2007
Return-Path: <[e-mail]>
Received: from s205.localdomain ([127.0.0.1])
        by s205.localdomain (8.12.8/8.12.8) with ESMTP id l3QH81N0003643
        for <[e-mail]>; Thu, 26 Apr 2007 13:08:01 -0400
Received: (from root@localhost)
        by s205.localdomain (8.12.8/8.12.8/Submit) id l3QH81VN003638
        for root; Thu, 26 Apr 2007 13:08:01 -0400
Date: Thu, 26 Apr 2007 13:08:01 -0400
From: root <[e-mail]>
Message-Id: <[e-mail]>
Subject: Output from your job        1
To: [e-mail]
 
111
1.sxw
1.txt
2.sxw
2.txt
3.txt
444.txt
445.txt
555
555~
anaconda-ks.cfg
example
example~
gong.tar
http
httpd-2.2.3-1.i386.rpm
install.log
install.log.syslog
?? Microsoft Word ??.doc
mysql
mysql-4.0.26.tar.gz
MySQL-client-5.1.7-0.i386.rpm
MySQL-server-5.1.7-0.i386.rpm
????????????????.part1.rar
????????????????.part2.rar
putty-0.59-installer.exe
????.rar
s03
s44
s444.txt
ssh??.doc
tmp
xplns_related
λ??-064100713.rar
/root
mkdir: cannot create directory `111': File exists
 
From [e-mail]  Thu Apr 26 13:13:01 2007
Return-Path: <[e-mail]>
Received: from s205.localdomain ([127.0.0.1])
        by s205.localdomain (8.12.8/8.12.8) with ESMTP id l3QHD0N0003659
        for <[e-mail]>; Thu, 26 Apr 2007 13:13:00 -0400
Received: (from root@localhost)
        by s205.localdomain (8.12.8/8.12.8/Submit) id l3QHD0OM003654
        for root; Thu, 26 Apr 2007 13:13:00 -0400
Date: Thu, 26 Apr 2007 13:13:00 -0400
From: root <[e-mail]>
Message-Id: <[e-mail]>
Subject: Output from your job        2
To: [e-mail]
 
111
1.sxw
1.txt
2.sxw
2.txt
3.txt
444.txt
445.txt
555
555~
anaconda-ks.cfg
example
example~
gong.tar
http
httpd-2.2.3-1.i386.rpm
install.log
install.log.syslog
job
?? Microsoft Word ??.doc
mysql
mysql-4.0.26.tar.gz
MySQL-client-5.1.7-0.i386.rpm
MySQL-server-5.1.7-0.i386.rpm
????????????????.part1.rar
????????????????.part2.rar
putty-0.59-installer.exe
????.rar
s03
s44
s444.txt
ssh??.doc
tmp
xplns_related
λ??-064100713.rar
/root
mkdir: cannot create directory `111': File exists


[root@s205 root]# at 12:00 6/6/07
warning: commands will be executed using (in order) a) $SHELL b) login shell c)
/bin/sh
at> ls
at> <EOT>
job 3 at 2007-06-06 12:00
[root@s205 root]# at 22:02 9/9/07
warning: commands will be executed using (in order) a) $SHELL b) login shell c)
/bin/sh
at> pwd
at> <EOT>
job 4 at 2007-09-09 22:02
[root@s205 root]# at 15:03 10/10/07
warning: commands will be executed using (in order) a) $SHELL b) login shell c)
/bin/sh
at> passwd yonghu2
at> <EOT>
job 5 at 2007-10-10 15:03
[root@s205 root]# atq
3       2007-06-06 12:00 a root
4       2007-09-09 22:02 a root
5       2007-10-10 15:03 a root

[root@s205 root]# atrm 4
[root@s205 root]# atq
3       2007-06-06 12:00 a root
5       2007-10-10 15:03 a root
[root@s205 root]# vi rootcron
38 13 * * * cat /etc/passwd
[root@s205 root]# crontab rootcron
[root@s205 root]# crontab -l
# DO NOT EDIT THIS FILE - edit the master and reinstall.
# (rootcron installed on Thu Apr 26 13:35:29 2007)
# (Cron version -- $Id: crontab.c,v 2.13 1994/01/17 03:20:37 vixie Exp $)
38 13 * * * cat /etc/passwd

[root@s205 root]# cd /var/spool/cron
You have new mail in /var/spool/mail/root
[root@s205 cron]# cat root
# DO NOT EDIT THIS FILE - edit the master and reinstall.
# (rootcron installed on Thu Apr 26 13:35:29 2007)
# (Cron version -- $Id: crontab.c,v 2.13 1994/01/17 03:20:37 vixie Exp $)
38 13 * * * cat /etc/passwd

From [e-mail]  Thu Apr 26 13:38:00 2007
Return-Path: <[e-mail]>
Received: from s205.localdomain ([127.0.0.1])
        by s205.localdomain (8.12.8/8.12.8) with ESMTP id l3QHc0N0003726
        for <[e-mail]>; Thu, 26 Apr 2007 13:38:00 -0400
Received: (from root@localhost)
        by s205.localdomain (8.12.8/8.12.8/Submit) id l3QHc0SC003724
        for root; Thu, 26 Apr 2007 13:38:00 -0400
Date: Thu, 26 Apr 2007 13:38:00 -0400
Message-Id: <[e-mail]>
From: [e-mail] (Cron Daemon)
To: [e-mail]
Subject: Cron <root@s205> cat /etc/passwd
X-Cron-Env: <SHELL=/bin/sh>
X-Cron-Env: <HOME=/root>
X-Cron-Env: <PATH=/usr/bin:/bin>
X-Cron-Env: <LOGNAME=root>
 
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
news:x:9:13:news:/etc/news:
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
rpm:x:37:37::/var/lib/rpm:/bin/bash
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
nscd:x:28:28:NSCD Daemon:/:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
rpc:x:32:32:Portmapper RPC user:/:/sbin/nologin
rpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin
nfsnobody:x:65534:65534:Anonymous NFS User:/var/lib/nfs:/sbin/nologin
mailnull:x:47:47::/var/spool/mqueue:/sbin/nologin
smmsp:x:51:51::/var/spool/mqueue:/sbin/nologin
pcap:x:77:77::/var/arpwatch:/sbin/nologin
xfs:x:43:43:X Font Server:/etc/X11/fs:/sbin/nologin
ntp:x:38:38::/etc/ntp:/sbin/nologin
gdm:x:42:42::/var/gdm:/sbin/nologin
unixstudy:x:500:500::/home/unixstudy:/bin/bash
tom:x:100:501::/home/tom:/bin/bash
bubba:x:501:503::/home/bubba:/bin/bash
yonghu2:x:502:505::/home/yonghu2:/bin/bash
mysql:x:101:102:MySQL server:/var/lib/mysql:/bin/bash
[root@s205 cron]# crontab -e


43 13 * * * cat /root/job

crontab: installing new crontab
[root@s205 cron]# crontab -l
# DO NOT EDIT THIS FILE - edit the master and reinstall.
# (/tmp/crontab.3733 installed on Thu Apr 26 13:42:17 2007)
# (Cron version -- $Id: crontab.c,v 2.13 1994/01/17 03:20:37 vixie Exp $)
43 13 * * * cat /root/job
[root@s205 cron]# crontab -r
[root@s205 cron]# crontab -l
no crontab for root



[root@s205 root]# vi ex02.c

#include <stdio.h>
int main()
{
 FILE *fp;
 fp=fopen("file2.txt","w");
fprintf(fp,"hello world!");
fclose(fp);
return(0);
}


[root@s205 root]# gcc ex02.c -o ex02.out
[root@s205 root]# ls
111              ex02.out                       ????????????????.part1.rar
1.sxw            example                        ????????????????.part2.rar
1.txt            example~                       putty-0.59-installer.exe
2.sxw            gong.tar                       ????.rar
2.txt            http                           rootcron
3.txt            httpd-2.2.3-1.i386.rpm         s03
444.txt          install.log                    s44
445.txt          install.log.syslog             s444.txt
555              job                            ssh??.doc
555~             ?? Microsoft Word ??.doc       tmp
anaconda-ks.cfg  mysql                          xplns_related
at               mysql-4.0.26.tar.gz            λ??-064100713.rar
at~              MySQL-client-5.1.7-0.i386.rpm
ex02.c           MySQL-server-5.1.7-0.i386.rpm
[root@s205 root]# ./ex02.out&
[1] 3788
[root@s205 root]# ls
111              ex02.out                       MySQL-server-5.1.7-0.i386.rpm
1.sxw            example                        ????????????????.part1.rar
1.txt            example~                       ????????????????.part2.rar
2.sxw            file2.txt                      putty-0.59-installer.exe
2.txt            gong.tar                       ????.rar
3.txt            http                           rootcron
444.txt          httpd-2.2.3-1.i386.rpm         s03
445.txt          install.log                    s44
555              install.log.syslog             s444.txt
555~             job                            ssh??.doc
anaconda-ks.cfg  ?? Microsoft Word ??.doc       tmp
at               mysql                          xplns_related
at~              mysql-4.0.26.tar.gz            λ??-064100713.rar
ex02.c           MySQL-client-5.1.7-0.i386.rpm
[1]+  Done                    ./ex02.out
[root@s205 root]# vi ex01.c



#include <stdio.h>
int main()
{
int i;
int j;
int k;
int sum;
for(i=0;i<32767;i++)
for(j=0;j<5000;j++)
for(k=0;k<5;k++)
sum=0;
for(i=0;i<10;i++)
printf("\n the value of i is %d\n",i);
return(0);
}

[root@s205 root]# gcc ex01.c -o ex01.out
[root@s205 root]# ./ex01.out&
[1] 3796
[root@s205 root]#
 the value of i is 0
 
 the value of i is 1
 
 the value of i is 2
 
 the value of i is 3
 
 the value of i is 4
 
 the value of i is 5
 
 the value of i is 6
 
 the value of i is 7
 
 the value of i is 8
 
 the value of i is 9

[root@s205 root]# ps
  PID TTY          TIME CMD
 3799 pts/1    00:00:00 bash
 3825 pts/1    00:00:00 ps

[root@s205 root]# vi ex03.c

#include <stdio.h>
int main()
{
 int i;
int j;
int k;
int sum;
for(i=0;i<32767;i++)
for(j=0;j<5000;j++)
for(k=0;k<5000;k++)
sum=0;
for(i=0;i<10;i++)
printf("\n the value of i is %d\n",i);
return(0);
}
[root@s205 root]# ./a.out&
[1] 3832

[root@s205 root]# cd /proc
[root@s205 proc]# ls
1     3250  3439  3570  3609  9            ide         misc        sysvipc
10    3262  3440  3575  3610  apm          interrupts  modules     tty
11    3283  3441  3582  3649  bus          iomem       mounts      uptime
15    3314  3442  3586  3799  cmdline      ioports     mtrr        version
2     3323  3443  3588  3832  cpuinfo      irq         net
3     3333  3444  3590  3835  devices      kcore       partitions
3034  3342  3487  3592  4     dma          kmsg        pci
3091  3353  3488  3596  5     driver       ksyms       self
3095  3412  3497  3598  6     execdomains  loadavg     slabinfo
3113  3421  3555  3599  7     fb           locks       stat
3199  3430  3566  3606  73    filesystems  mdstat      swaps
3236  3438  3568  3608  8     fs           meminfo     sys

[root@s205 proc]# cd 3832
[root@s205 3832]# ls
cmdline  cwd  environ  exe  fd  maps  mem  mounts  root  stat  statm  status

[root@s205 3832]# cat status
Name:   a.out
State:  R (running)
Tgid:   3832
Pid:    3832
PPid:   3799
TracerPid:      0
Uid:    0       0       0       0
Gid:    0       0       0       0
FDSize: 256
Groups: 0 1 2 3 4 6 10
VmSize:     1336 kB
VmLck:         0 kB
VmRSS:       220 kB
VmData:       12 kB
VmStk:         8 kB
VmExe:         4 kB
VmLib:      1292 kB
SigPnd: 0000000000000000
SigBlk: 0000000000000000
SigIgn: 8000000000000000
SigCgt: 0000000000000000
CapInh: 0000000000000000
CapPrm: 00000000fffffeff
CapEff: 00000000fffffeff