04 Sep 2008 Share a bash session using screen
This is a short post on how you can “share” a bash session/prompt with other users.
- User A connects to the server and types in the command
# screen
- User A hist the key combination <Ctrl + a> and the type
:multiuser on
- User B connects to the same server as user A and can the join the session by typing
# screen -x
Serveral users can connect and share the same session at once.
To close the screen session just use the key combination <Ctrl + a>
Posted by Hans-Henry Jakobsen
23 Jun 2008 Oneliner to determine directory size
This is a simple oneliner to determine which user has used most diskspace in their /home directory
du -sm $(find /home -type d -maxdepth 1 -xdev) | sort -g
The result could look something like this
... 215 /home/userT 1367 /home/userB 10865 /home/userL 25326 /home/userY 116328 /home/userH 154426 /home/
The numbers to the left is size i MB.
Tags: bash
Posted by Hans-Henry Jakobsen
03 Jun 2008 Generate a /etc/hosts file from the command line
This is a simple example of how you can populate a /etc/hosts file with 100 IPs and hosts from the command line
# N=1; for i in $(seq -w 100); do echo "192.168.99.$N host$i"; P=$(expr $P + 1); done >> /etc/hosts
The result file /etc/hosts
192.168.99.201 host001 192.168.99.201 host002 192.168.99.201 host003 192.168.99.201 host004 192.168.99.201 host005 192.168.99.201 host006 192.168.99.201 host007 192.168.99.201 host008 192.168.99.201 host009 192.168.99.201 host010 192.168.99.201 host011 192.168.99.201 host012 192.168.99.201 host013 192.168.99.201 host014 192.168.99.201 host015 192.168.99.201 host016 192.168.99.201 host017 192.168.99.201 host018 192.168.99.201 host019 192.168.99.201 host020 ...
Tags: bash
Posted by Hans-Henry Jakobsen
25 Feb 2008 My 10 most used linux commands
This is a oneliner bash command to determine my 10 most used linux commands according to my history file
history | awk '{CMD[$2]++;count++;}END { for (a in CMD)print CMD[a] " " CMD[a]/count*100 "% " a;}' | grep -v "./" | column -c3 -s " " -t | sort -nr | nl | head -n10
The result
1 188 37.6% vi
2 38 7.6% ls
3 24 4.8% cat
4 22 4.4% apt-get
5 12 2.4% date
6 11 2.2% tail
7 11 2.2% cd
8 10 2% rm
9 10 2% man
10 9 1.8% basename
It looks like i use vim a lot on my home server. You should try it yourself and see what commands you use the most.
Source: http://linux.byexamples.com
Tags: awk, bash, count, grep, head, nl, sort
Posted by Hans-Henry Jakobsen
21 Feb 2008 Apache web connections pr hour
This is a bash oneliner to show Apache web connections pr hour. It lists up the IPs that has accessed your webserver and the amount og accesses.
# cat /var/log/apache2/access_log_pario.no | grep "21/Jan/2008:.." | awk {' print $4":"$1 '} | sed 's/\[//g' | awk -F : {' print $1":"$2"\t\t"$5 '} | sort | uniq -c
Example output
37 21/Jan/2008:00 192.168.0.10
This shows that I had 37 hits from 00:00 – 01:00 in 20th February 2008.
Tags: Apache, awk, bash, grep, sed
Posted by Hans-Henry Jakobsen
