https://raghavxk8s.com/categories/system-admin-cmds/ Recent content in System Admin Cmds on AI Infra Hugo -- gohugo.io en-us Fri, 14 Jun 2019 09:20:00 +0000 https://raghavxk8s.com/post/bash-shortcuts/ Fri, 14 Jun 2019 09:20:00 +0000 https://raghavxk8s.com/post/bash-shortcuts/ Show and execute most recent command $ echo Hello World! $ !! echo Hello World! Hello World! Execute/View most recent command that starts with given key word $ echo Hello World! $ !echo echo Hello World! Hello World! -- Only view the command(Do not execute) $ !echo:p Option ":p" only prints the command without executing it. Arguments of last command can be referred using ‘!*’ $ echo Hello World! https://raghavxk8s.com/post/sys-admin-cmds-4/ Wed, 12 Jun 2019 17:57:21 +0000 https://raghavxk8s.com/post/sys-admin-cmds-4/ Run levels are Run level 0 is matched by poweroff.target (and runlevel0.target is a symbolic link to poweroff.target). Run level 1 is matched by rescue.target (and runlevel1.target is a symbolic link to rescue.target). Run level 3 is emulated by multi-user.target (and runlevel3.target is a symbolic link to multi-user.target). Run level 5 is emulated by graphical.target (and runlevel5.target is a symbolic link to graphical.target). Run level 6 is emulated by reboot. https://raghavxk8s.com/post/sys-admin-cmds-3/ Wed, 12 Jun 2019 15:53:19 +0000 https://raghavxk8s.com/post/sys-admin-cmds-3/ TODO : extend existing volumes mount $ mount <source> <dest> $ mount /dev/sda2 mountDestDir --- list all mount points $ mount -l --- list all mount points of given type. $ mount -l -t <type> find -- find by name $ find -name <name> -- find not matching name $ find -not -name <name-to-avoid> -- find by type $ find / -type <type> <name> <type> could be one of f = file d = directory l = symbolic link c = character devices b = block devices e. https://raghavxk8s.com/post/sys-admin-cmds-2/ Wed, 12 Jun 2019 01:22:21 +0000 https://raghavxk8s.com/post/sys-admin-cmds-2/ display inode details for a file $ stat <file> $ stat /etc/passwd --- Output --- File: `/etc/passwd' Size: 2026 Blocks: 8 IO Block: 4096 regular file Device: 811h/2065d Inode: 752010 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2007-08-20 23:19:20.000000000 +0530 Modify: 2007-07-07 00:06:56.000000000 +0530 Change: 2007-07-07 00:06:56.000000000 +0530 Create a user & group --- create a user & group $ sudo useradd -m testuser --- set passwd for the user $ sudo passwd testuser --- create a group sudo groupadd <groupname> $ sudo groupadd testgroup Adding user to a group sudo usermod -a -G <group> <user> $ sudo usermod -a -G testgroup testuser list users for a given group $ grep <username> /etc/group $ grep testuser /etc/group User passwords User encrypted passwords are stored in /etc/shadow. https://raghavxk8s.com/post/sys-admin-cmds-1/ Sun, 19 May 2019 06:34:32 +0000 https://raghavxk8s.com/post/sys-admin-cmds-1/ lscpu list of cpus. lsmem list of memory. lsof (list open files) lsof -i tcp:80 df (disk free space) Display free disk space Filesystem Size Used Avail Use% Mounted on /dev/xvda1 32G 4.7G 26G 16% / tmpfs 1.9G 0 1.9G 0% /dev/shm du (disk space usage) du - estimate file space usage du -sh /var/* id $ id uid=501(operations) gid=100(users) groups=100(users) curl curl -I -s google.