Linux commands
From Wsms
Examples of commands and simple scripts in bash.
Contents |
mkfs.vfat
You can make a FAT partition with the mkfs.vfat command. FAT partitions can be read and written by both Linux and Windows. The maximum file size is 2.0G, and FAT does not support Linux or NTFS file ownerships and permissions.
# mkfs.vfat -v -n SHARE /dev/hda6
This command formates the sixth partition of the first IDE hard drive. The volume name, or label, will be SHARE. The -v is the verbose flag. Only the root user can use the mkfs.vfat command.
nconnections.sh
This simple shell script lets you keep an eye on how many users are watching your screen 0 using vncviewer. See Xvnc_Fedora_setup_howto
#!/usr/bin/env bash # George Geller # 20061027 # Show how many connections we have to our port 5900. NCONN=`netstat -ant | grep 192.168.1.12:5900 | wc -l` echo -n "$NCONN connections"
You have to replace 192.168.1.12 with the IP address for the interface where users connect. Then you can run watch:
$ watch ./nconnections.sh
find
Find all files, or just ones that are interesting. List them, or do something with them.
Find all files in /etc directory newer than ten minutes old:
# find /etc -mmin -10 -print
Find all files in /etc directory newer than one day old:
# find /etc -mtime -1 -print
Find all the .wmv files and get a long listing:
# find / -name "*.wmv" -exec ls -l '{}' \;
Find all the files in your home directory and save the list to another file:
# find ~ -name "*" -print > find.out
Find all the files that are symbolic links:
# find . -type l -print
Keep a hard disk like the Seagate_FreeAgent somewhat busy so it doesn't go to sleep or something:
# nice find /mnt/sda3/ -type f -exec cat '{}' > /dev/null \;
List empty directories:
$ find -type d -empty
Remove empty directories:
[ggeller@arthur George]$ find -depth -type d -empty -exec rmdir '{}' \;
Prettify the output by removing the initial ./:
ggeller@arthur:~$ find . -name "*.log" | perl -ne 's/^.\/// ; print'
tunnel with ssh
This sets up an ssh tunnel from a port on wsNN to a port on rop.
[user@wsNN ~]$ ssh -f -N -L 5901:localhost:5901 user@rop.ncc.sdccd.net
kill
kill is the Linux command to send a message to a process, or to kill it:
[user@arthur ~]$ kill -9 <pid>
Use something like pstree -pu to get the pid for the process that you need to kill. You can use different integer values to send different messages. kill -l (for list) prints a list of the possible messages.
[ggeller@arthur ~]$ kill -l 1) SIGHUP 2) SIGINT 3) SIGQUIT 4) SIGILL 5) SIGTRAP 6) SIGABRT 7) SIGBUS 8) SIGFPE 9) SIGKILL 10) SIGUSR1 11) SIGSEGV 12) SIGUSR2 13) SIGPIPE 14) SIGALRM 15) SIGTERM 16) SIGSTKFLT 17) SIGCHLD 18) SIGCONT 19) SIGSTOP 20) SIGTSTP 21) SIGTTIN 22) SIGTTOU 23) SIGURG 24) SIGXCPU 25) SIGXFSZ 26) SIGVTALRM 27) SIGPROF 28) SIGWINCH 29) SIGIO 30) SIGPWR 31) SIGSYS 34) SIGRTMIN 35) SIGRTMIN+1 36) SIGRTMIN+2 37) SIGRTMIN+3 38) SIGRTMIN+4 39) SIGRTMIN+5 40) SIGRTMIN+6 41) SIGRTMIN+7 42) SIGRTMIN+8 43) SIGRTMIN+9 44) SIGRTMIN+10 45) SIGRTMIN+11 46) SIGRTMIN+12 47) SIGRTMIN+13 48) SIGRTMIN+14 49) SIGRTMIN+15 50) SIGRTMAX-14 51) SIGRTMAX-13 52) SIGRTMAX-12 53) SIGRTMAX-11 54) SIGRTMAX-10 55) SIGRTMAX-9 56) SIGRTMAX-8 57) SIGRTMAX-7 58) SIGRTMAX-6 59) SIGRTMAX-5 60) SIGRTMAX-4 61) SIGRTMAX-3 62) SIGRTMAX-2 63) SIGRTMAX-1 64) SIGRTMAX
The meaning of most of the values is an advanced topic. You can get a little information about them from man kill, man signal, and man signal.h
wget
wget fetches files(s) from the internet to your current working directory. To get an rpm file:
[ggeller@arthur ~]$ wget http://prdownloads.sourceforge.net/webadmin/webmin-1.300-1.noarch.rpm
To get an entire website:
[ggeller@arthur ~]$ wget -r http://www.buckysicecream.com
The -r option generally works for static web sites, but not so well for dynamic sites. wget works with the http and ftp protocols. It doesn't work for sites that required logins.
rsync
Efficiently copy stuff.
rsync is great for synchronizing stuff over the web.
Copy everything from your directory on the rop server to your home computer:
[ggeller@arthur ~]$ rsync -av georgeg@rop.ncc.sdccd.net: georgeg@rop.ncc.sdccd.net's password: receiving file list ... done ./ .ICEauthority .Xauthority .bash_history .bash_logout .bash_profile ...
See also rsync with ssh keys
stat
Stat is a command that shows a few things that ls -l doesn't:
[ggeller@ws05 ~]$ stat RMAIL File: `RMAIL' Size: 183 Blocks: 8 IO Block: 4096 regular file Device: fd00h/64768d Inode: 1372178 Links: 1 Access: (0664/-rw-rw-r--) Uid: ( 500/ ggeller) Gid: ( 500/ ggeller) Access: 2007-02-06 11:17:58.000000000 -0800 Modify: 2007-02-06 11:10:42.000000000 -0800 Change: 2007-02-06 11:10:42.000000000 -0800
ntpd and ntpdate
ntpd is the ntp deamon. It is supposed to keep the time on you Linux box synchronized with reliable time sources over the internet. ntpd doesn't seem to work very will on virtual machines running VMWare. ntpdate is a one-shot version (more or less) of ntpd. The most common way to use ntpdate is:
[root@localhost ~]# service ntpd stop Shutting down ntpd: [ OK ] [root@localhost ~]# ntpdate pool.ntp.org 15 Mar 16:10:22 ntpdate[2902]: step time server 216.165.129.244 offset 199.609837 sec [root@localhost ~]# service ntpd start 15 Mar 16:10:40 ntpdate[2910]: step time server 64.34.193.47 offset 6.367052 sec Starting ntpd: [ OK ]
games
There are some Linux games available:
- Tuxracer
- Scorched 3D
- Doom/Quake
see also
http://www.linuxjournal.com/article/8412
20061215
ntpd
su
ping
nohup
Linux Commands/Find
gnome-volume-properties
