My RHEL Notes
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general notes
$ cmd [-opt] [arguments]
cmd uses $PATH and arguments uses $PWD. Arguments are local to current working directory
Press TAB TAB to list available commands in $PATH or list available arguments in $PWD.
managing system resources
Ctrl+Z jobs fg %[job #] ps [-fax]
Process Status can be suspended (S+PROCESS STATE CODES in $ ps man page to view), stopped (T), running (R+), zombie
running process is flagged to be scheduled in CPU cycles
# ps -ax Command column square brackets [ ] mean kernel started process. kill -l // list kill options process priority # nice cmd # renice cmd # jobs // to get job # kill -KILL %[job #] // to kill by job #
disk usage
use du command # du -sh /* 2> /dev/null // use STD ERROR to bit bucket # ps -eo "%c %n %y" // see ps man page, like %P & %U
Software Management
# rpm -qf # rpm -ql # rpm -V # rpm -vi # rpm -qa yum resolves dependencies rpm installs & deletes # ls /etc/yum.repos.d/
man pages
$ man -k record | grep -i dvd # man -k pdf
network stuff
$ mtr [destination]
users & groups
# egrep 'dave|darth|luke' /etc/{passwd,group,shadow}
permissions
umask blocks out bits
special permissions
<insert graphics example>
[student@desktop12 test]$ pwd /home/student/test [student@desktop12 test]$ touch file1 [student@desktop12 test]$ touch file2 [student@desktop12 test]$ touch file3 [student@desktop12 test]$ touch file4 [student@desktop12 test]$ touch file5 [student@desktop12 test]$ touch file6 [student@desktop12 test]$ touch file7 [student@desktop12 test]$ chmod 1777 file1 [student@desktop12 test]$ chmod 2777 file2 [student@desktop12 test]$ chmod 3777 file3 [student@desktop12 test]$ chmod 4777 file4 [student@desktop12 test]$ chmod 5777 file5 [student@desktop12 test]$ chmod 6777 file6 [student@desktop12 test]$ chmod 7777 file7 [student@desktop12 test]$ ls -l total 0 -rwxrwxrwt. 1 student student 0 Sep 29 10:19 file1 -rwxrwsrwx. 1 student student 0 Sep 29 10:19 file2 -rwxrwsrwt. 1 student student 0 Sep 29 10:19 file3 -rwsrwxrwx. 1 student student 0 Sep 29 10:19 file4 -rwsrwxrwt. 1 student student 0 Sep 29 10:19 file5 -rwsrwsrwx. 1 student student 0 Sep 29 10:19 file6 -rwsrwsrwt. 1 student student 0 Sep 29 10:20 file7 [student@desktop12 test]$
admin remote system
$ ssh -X hostname
$ gedit filename
ssh-copy-id
$ cd ~; tar -zcvf newtarball.tgz .
general services
/etc/services
/etc/init.d
/etc/inittab
chkconfig
service
netstat
pending categorization
# ldd /usr/bin/sshd