$ SOURCEDIRS=".ssh .gnupg .gitconfig bin Documents Desktop logs stuff"
$ TARGETDIR="/media/external/BACKUP"
$ mkdir ${TARGETDIR}
$ cd ~/
$ du -smxc ${SOURCEDIRS}
$ rsync -avhpzx --progress --stats ${SOURCEDIRS} "${TARGETDIR}/"
Lock the screen and suspend the system (to RAM)
$ gnome-screensaver-command -l && dbus-send --print-reply --system --dest=org.freedesktop.DeviceKit.Power --type=method_call --reply-timeout=6000 /org/freedesktop/DeviceKit/Power org.freedesktop.DeviceKit.Power.Suspend
(Alternative) Suspend to RAM
# cat /sys/power/state
freeze mem disk
# echo -n mem > /sys/power/state
Resize images and strip EXIF data
arno@homepc:~/photos$ for i in $(ls); do convert $i -resize 2800x1800 -quality 80 -strip ${i}-converted.jpg ;done
When you updated your system packages check for deleted file descriptors and make sure that libraries loaded in memory are not old. If necessary, restart the service.
# lsof -n |grep DEL
# diff /etc/rsyslog.conf.20121204 /etc/rsyslog.conf
38c38
< #kern.* /dev/console --- > kern.* /var/log/kern.log
# service rsyslog restart
Shutting down system logger: [ OK ]
Starting system logger: [ OK ]
# cat /var/log/kern.log
Dec 4 09:37:31 hostname kernel: imklog 5.8.10, log source = /proc/kmsg started.
$ date +"%Y%m%d"
20121204
$ TZ=XYZ+24 date +"%Y%m%d"
20121203
$ date --date='yesterday' +"%Y%m%d"
20121222
$ date --date='5 days ago' +"%Y%m%d"
20121218
# svn checkout svn://svn.mplayerhq.hu/mplayer/trunk mplayer
# cd mplayer
# svn update
(Optional) # ./configure --yasm='' --extra-cflags="-O3"
# ./configure --yasm=''
# cd ffmpeg/
# ./configure --disable-yasm
# cd ..
# make
# ./mplayer
Automatic ssh login without keys
# yum install expect
$ expect -c 'spawn ssh admin@server.com;expect password;send "Y0uRPassword\n";interact'
With ssh keys (in case when /etc/sudoers setup in use)
$ ssh-copy-id admin@server.com # Do this once. This adds your ~/.ssh/id_rsa.pub to server's ~/.ssh/authorized_keys file
$ expect -c 'spawn ssh admin@server.com;expect admin;send "sudo su -\n";expect password;send "Y0uRPassword\n";interact'
Testing SSH port via SOCKS proxy
$ /usr/bin/nc -X 5 -x 120.70.70.77:1080 -vz 19.100.2.51 22
Connection to 19.100.2.51 22 port [tcp/ssh] succeeded!
Establishing SSH connection to a remote server behind proxy
# ssh -o "ProxyCommand /usr/bin/nc -X 5 -x 120.70.70.77:1080 %h %p" user@19.100.2.51
To make user SSH configuration, edit yours ~/.ssh/config config as follows.
# Customer1
Host 18.100.*
ProxyCommand /usr/bin/nc -X 5 -x 120.70.70.77:1080 %h %p
# Customer2
Host 19.100.*
ProxyCommand /usr/bin/nc -X 5 -x 120.70.70.77:1080 %h %p
After that you can directly connect remote servers behind the proxy, for example: ssh user@19.100.2.51
When watching a movie you don’t want your screen to blank or screensaver to lock.
#!/usr/bin/env sh
# moviemode.sh
trap 'echo Exiting..; xset +dpms ; xset s on; exit' SIGINT SIGQUIT
set -x
xset -dpms
xset s off
gnome-screensaver-command -i
# find /path/to/ -type f -name "*.zip" |xargs -I% sh -c '(unzip -l % *jpg 2>/dev/null|grep Pattern) && echo "ZIP: "%'
[root@rhel ~]# cp /etc/motd ./test
[root@rhel ~]# hexdump -C test |tail -5
000003e0 0a 0a 3d 3d 3d 3d 3e 20 54 65 78 74 20 6f 66 20 |..====> Text of |
000003f0 74 68 69 73 20 6d 65 73 73 61 67 65 20 69 73 20 |this message is |
00000400 69 6e 20 2f 65 74 63 2f 6d 6f 74 64 20 3c 3d 3d |in /etc/motd <==|
00000410 3d 3d 0a |==.|
00000413
[root@rhel ~]# dd if=/dev/zero of=/root/test ibs=1M count=10 obs=1M oflag=append conv=notrunc
10+0 records in
10+0 records out
10485760 bytes (10 MB) copied, 0.0208541 s, 503 MB/s
[root@rhel ~]# hexdump -C test |tail -5
00000410 3d 3d 0a 00 00 00 00 00 00 00 00 00 00 00 00 00 |==..............|
00000420 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00a00410 00 00 00 |...|
00a00413
$ wget -c http://download.documentfoundation.org/libreoffice/stable/4.1.2/rpm/x86_64/LibreOffice_4.1.2_Linux_x86-64_rpm.tar.gz.meta4 -O - 2>/dev/null|grep url
Besides coreutils, openssl also gives you a way to calculate various checksums (see ‘man dgst’)
Using OpenSSL
$ openssl dgst -md5 /etc/services
MD5(/etc/services)= 35435ea447c19f0ea5ef971837ab9ced
$ openssl dgst -sha256 /etc/services
SHA256(/etc/services)= f0c4af9261e7e6193db0bbb8f335c0f0c094d8d7aa428e5d8cbb674f2e13b2ef
Using perl
$ cat bin/md5sum.pl
#!/bin/env perl
use Digest::MD5;
use IO::File;
my $chk = Digest::MD5->new();
foreach my $file (@ARGV)
{
$chk->addfile(IO::File->new($file));
print "$file -> ",$chk->hexdigest,"\n";
}
$ md5sum.pl /etc/services /etc/motd
/etc/services -> 35435ea447c19f0ea5ef971837ab9ced
/etc/motd -> 7bd665b73c9f9f2938c561175e5f8db1
In AIX
$ csum -h MD5 /etc/services
Feel free to improve this article ! ;)
This happened to me after upgrading to Ubuntu 13.10
If you started your system after it was suspended and there seem to be no network after wake-up, then you should run following
root@homepc:~# nmcli nm status
root@homepc:~# nmcli nm sleep false
root@homepc:~# cat /etc/pm/sleep.d/20_mouse-speed
#!/bin/sh
#
# Adjust mouse speed on resume/thaw after sleep/hibernate.
# Should work for all active users in the system using X.
#
case $1 in
resume|thaw)
/usr/bin/who |/usr/bin/sort -u -k1,1 |/usr/bin/awk '{print $1, $NF}' | /usr/bin/tr -d ')''(' |while read USER DISPLAY; do /bin/su ${USER} -c "(sleep 3 && DISPLAY=${DISPLAY} /usr/bin/xset m 1) &" ; done
;;
esac
SSD boosts system startup, however lightDM needs a little while to start properly in such case. Below is the workaround, just add “sleep 2” or more seconds to make sure that you won’t have black screen while booting Ubuntu 13.04.
root@homepc:~# diff -u /etc/init/lightdm.conf.arnobkp /etc/init/lightdm.conf
--- /etc/init/lightdm.conf.arnobkp 2013-04-23 11:10:26.000000000 +0200
+++ /etc/init/lightdm.conf 2013-08-04 18:14:39.105140142 +0200
@@ -43,6 +43,7 @@
fi
fi
+ sleep 2 # workaround for SSD disk so that no black screen experienced. http://www.youtube.com/watch?v=402YWC2LkjA
exec lightdm
end script