[root@s205 root]# at 1:08pmwarning: commands will be executed using (in order) a) $SHELL b) login shell c)/bin/shat> lsat> pwdat> mkdir 111at> <EOT>job 1 at 2007-04-26 13:08[root@s205 root]# cat /var/spool/mail/rootFrom root@s205.localdomain  Thu Apr 26 13:08:01 2007Return-Path: <root@s205.localdomain>Received: from s205.localdomain ([127.0.0.1])        by s205.localdomain (8.12.8/8.12.8) with ESMTP id l3QH81N0003643        for <root@s205.localdomain>; Thu, 26 Apr 2007 13:08:01 -0400Received: (from root@localhost)        by s205.localdomain (8.12.8/8.12.8/Submit) id l3QH81VN003638        for root; Thu, 26 Apr 2007 13:08:01 -0400Date: Thu, 26 Apr 2007 13:08:01 -0400From: root <root@s205.localdomain>Message-Id: <200704261708.l3QH81VN003638@s205.localdomain>Subject: Output from your job        1To: root@s205.localdomain 1111.sxw1.txt2.sxw2.txt3.txt444.txt445.txt555555~anaconda-ks.cfgexampleexample~gong.tarhttphttpd-2.2.3-1.i386.rpminstall.loginstall.log.syslog?? Microsoft Word ??.docmysqlmysql-4.0.26.tar.gzMySQL-client-5.1.7-0.i386.rpmMySQL-server-5.1.7-0.i386.rpm????????????????.part1.rar????????????????.part2.rarputty-0.59-installer.exe????.rars03s44s444.txtssh??.doctmpxplns_relatedλ??-064100713.rar/rootmkdir: cannot create directory `111': File exists[root@s205 root]# at -f job 13:13warning: commands will be executed using (in order) a) $SHELL b) login shell c)/bin/shjob 2 at 2007-04-26 13:13[root@s205 root]# cat /var/spool/mail/rootFrom root@s205.localdomain  Thu Apr 26 13:08:01 2007Return-Path: <root@s205.localdomain>Received: from s205.localdomain ([127.0.0.1])        by s205.localdomain (8.12.8/8.12.8) with ESMTP id l3QH81N0003643        for <root@s205.localdomain>; Thu, 26 Apr 2007 13:08:01 -0400Received: (from root@localhost)        by s205.localdomain (8.12.8/8.12.8/Submit) id l3QH81VN003638        for root; Thu, 26 Apr 2007 13:08:01 -0400Date: Thu, 26 Apr 2007 13:08:01 -0400From: root <root@s205.localdomain>Message-Id: <200704261708.l3QH81VN003638@s205.localdomain>Subject: Output from your job        1To: root@s205.localdomain 1111.sxw1.txt2.sxw2.txt3.txt444.txt445.txt555555~anaconda-ks.cfgexampleexample~gong.tarhttphttpd-2.2.3-1.i386.rpminstall.loginstall.log.syslog?? Microsoft Word ??.docmysqlmysql-4.0.26.tar.gzMySQL-client-5.1.7-0.i386.rpmMySQL-server-5.1.7-0.i386.rpm????????????????.part1.rar????????????????.part2.rarputty-0.59-installer.exe????.rars03s44s444.txtssh??.doctmpxplns_relatedλ??-064100713.rar/rootmkdir: cannot create directory `111': File exists From root@s205.localdomain  Thu Apr 26 13:13:01 2007Return-Path: <root@s205.localdomain>Received: from s205.localdomain ([127.0.0.1])        by s205.localdomain (8.12.8/8.12.8) with ESMTP id l3QHD0N0003659        for <root@s205.localdomain>; Thu, 26 Apr 2007 13:13:00 -0400Received: (from root@localhost)        by s205.localdomain (8.12.8/8.12.8/Submit) id l3QHD0OM003654        for root; Thu, 26 Apr 2007 13:13:00 -0400Date: Thu, 26 Apr 2007 13:13:00 -0400From: root <root@s205.localdomain>Message-Id: <200704261713.l3QHD0OM003654@s205.localdomain>Subject: Output from your job        2To: root@s205.localdomain 1111.sxw1.txt2.sxw2.txt3.txt444.txt445.txt555555~anaconda-ks.cfgexampleexample~gong.tarhttphttpd-2.2.3-1.i386.rpminstall.loginstall.log.syslogjob?? Microsoft Word ??.docmysqlmysql-4.0.26.tar.gzMySQL-client-5.1.7-0.i386.rpmMySQL-server-5.1.7-0.i386.rpm????????????????.part1.rar????????????????.part2.rarputty-0.59-installer.exe????.rars03s44s444.txtssh??.doctmpxplns_relatedλ??-064100713.rar/rootmkdir: cannot create directory `111': File exists[root@s205 root]# at 12:00 6/6/07warning: commands will be executed using (in order) a) $SHELL b) login shell c)/bin/shat> lsat> <EOT>job 3 at 2007-06-06 12:00[root@s205 root]# at 22:02 9/9/07warning: commands will be executed using (in order) a) $SHELL b) login shell c)/bin/shat> pwdat> <EOT>job 4 at 2007-09-09 22:02[root@s205 root]# at 15:03 10/10/07warning: commands will be executed using (in order) a) $SHELL b) login shell c)/bin/shat> passwd yonghu2at> <EOT>job 5 at 2007-10-10 15:03[root@s205 root]# atq3       2007-06-06 12:00 a root4       2007-09-09 22:02 a root5       2007-10-10 15:03 a root[root@s205 root]# atrm 4[root@s205 root]# atq3       2007-06-06 12:00 a root5       2007-10-10 15:03 a root[root@s205 root]# vi rootcron38 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/cronYou 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/passwdFrom root@s205.localdomain  Thu Apr 26 13:38:00 2007Return-Path: <root@s205.localdomain>Received: from s205.localdomain ([127.0.0.1])        by s205.localdomain (8.12.8/8.12.8) with ESMTP id l3QHc0N0003726        for <root@s205.localdomain>; Thu, 26 Apr 2007 13:38:00 -0400Received: (from root@localhost)        by s205.localdomain (8.12.8/8.12.8/Submit) id l3QHc0SC003724        for root; Thu, 26 Apr 2007 13:38:00 -0400Date: Thu, 26 Apr 2007 13:38:00 -0400Message-Id: <200704261738.l3QHc0SC003724@s205.localdomain>From: root@s205.localdomain (Cron Daemon)To: root@s205.localdomainSubject: Cron <root@s205> cat /etc/passwdX-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/bashbin:x:1:1:bin:/bin:/sbin/nologindaemon:x:2:2:daemon:/sbin:/sbin/nologinadm:x:3:4:adm:/var/adm:/sbin/nologinlp:x:4:7:lp:/var/spool/lpd:/sbin/nologinsync:x:5:0:sync:/sbin:/bin/syncshutdown:x:6:0:shutdown:/sbin:/sbin/shutdownhalt:x:7:0:halt:/sbin:/sbin/haltmail:x:8:12:mail:/var/spool/mail:/sbin/nologinnews:x:9:13:news:/etc/news:uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologinoperator:x:11:0:operator:/root:/sbin/nologingames:x:12:100:games:/usr/games:/sbin/nologingopher:x:13:30:gopher:/var/gopher:/sbin/nologinftp:x:14:50:FTP User:/var/ftp:/sbin/nologinnobody:x:99:99:Nobody:/:/sbin/nologinrpm:x:37:37::/var/lib/rpm:/bin/bashvcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologinnscd:x:28:28:NSCD Daemon:/:/sbin/nologinsshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologinrpc:x:32:32:Portmapper RPC user:/:/sbin/nologinrpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologinnfsnobody:x:65534:65534:Anonymous NFS User:/var/lib/nfs:/sbin/nologinmailnull:x:47:47::/var/spool/mqueue:/sbin/nologinsmmsp:x:51:51::/var/spool/mqueue:/sbin/nologinpcap:x:77:77::/var/arpwatch:/sbin/nologinxfs:x:43:43:X Font Server:/etc/X11/fs:/sbin/nologinntp:x:38:38::/etc/ntp:/sbin/nologingdm:x:42:42::/var/gdm:/sbin/nologinunixstudy:x:500:500::/home/unixstudy:/bin/bashtom:x:100:501::/home/tom:/bin/bashbubba:x:501:503::/home/bubba:/bin/bashyonghu2:x:502:505::/home/yonghu2:/bin/bashmysql:x:101:102:MySQL server:/var/lib/mysql:/bin/bash[root@s205 cron]# crontab -e43 13 * * * cat /root/jobcrontab: 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 -lno 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]# ls111              ex02.out                       ????????????????.part1.rar1.sxw            example                        ????????????????.part2.rar1.txt            example~                       putty-0.59-installer.exe2.sxw            gong.tar                       ????.rar2.txt            http                           rootcron3.txt            httpd-2.2.3-1.i386.rpm         s03444.txt          install.log                    s44445.txt          install.log.syslog             s444.txt555              job                            ssh??.doc555~             ?? Microsoft Word ??.doc       tmpanaconda-ks.cfg  mysql                          xplns_relatedat               mysql-4.0.26.tar.gz            λ??-064100713.rarat~              MySQL-client-5.1.7-0.i386.rpmex02.c           MySQL-server-5.1.7-0.i386.rpm[root@s205 root]# ./ex02.out&[1] 3788[root@s205 root]# ls111              ex02.out                       MySQL-server-5.1.7-0.i386.rpm1.sxw            example                        ????????????????.part1.rar1.txt            example~                       ????????????????.part2.rar2.sxw            file2.txt                      putty-0.59-installer.exe2.txt            gong.tar                       ????.rar3.txt            http                           rootcron444.txt          httpd-2.2.3-1.i386.rpm         s03445.txt          install.log                    s44555              install.log.syslog             s444.txt555~             job                            ssh??.docanaconda-ks.cfg  ?? Microsoft Word ??.doc       tmpat               mysql                          xplns_relatedat~              mysql-4.0.26.tar.gz            λ??-064100713.rarex02.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]# ls1     3250  3439  3570  3609  9            ide         misc        sysvipc10    3262  3440  3575  3610  apm          interrupts  modules     tty11    3283  3441  3582  3649  bus          iomem       mounts      uptime15    3314  3442  3586  3799  cmdline      ioports     mtrr        version2     3323  3443  3588  3832  cpuinfo      irq         net3     3333  3444  3590  3835  devices      kcore       partitions3034  3342  3487  3592  4     dma          kmsg        pci3091  3353  3488  3596  5     driver       ksyms       self3095  3412  3497  3598  6     execdomains  loadavg     slabinfo3113  3421  3555  3599  7     fb           locks       stat3199  3430  3566  3606  73    filesystems  mdstat      swaps3236  3438  3568  3608  8     fs           meminfo     sys[root@s205 proc]# cd 3832[root@s205 3832]# lscmdline  cwd  environ  exe  fd  maps  mem  mounts  root  stat  statm  status[root@s205 3832]# cat statusName:   a.outState:  R (running)Tgid:   3832Pid:    3832PPid:   3799TracerPid:      0Uid:    0       0       0       0Gid:    0       0       0       0FDSize: 256Groups: 0 1 2 3 4 6 10VmSize:     1336 kBVmLck:         0 kBVmRSS:       220 kBVmData:       12 kBVmStk:         8 kBVmExe:         4 kBVmLib:      1292 kBSigPnd: 0000000000000000SigBlk: 0000000000000000SigIgn: 8000000000000000SigCgt: 0000000000000000CapInh: 0000000000000000CapPrm: 00000000fffffeffCapEff: 00000000fffffeff