linux general tips
Memory
-> memory usage per process
---------------------------------------------------------------
ps -eo pid,ppid,rss,vsize,pcpu,pmem,cmd -ww --sort=pid
or
run top
press SHIT+f
choose n (memory)
:)
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-> free mem
------------------------------
# free -m will show in mb
# use also vmstat
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-> show process tree
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pstree
or
pstree -p
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-> bash
-> howto become a root, do something, and exit with bash script
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#!/bin/bash
echo "i am root"
su noch -c "echo alalala ; whoami; exit";
echo "i am root again"
whoami
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-> howto debug bash script
------------------------
add following line in the script
set -o xtrace
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-> finding files from plain console without mc
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for instance grep in header files for some word
find . -name \*.h | xargs grep your_word
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-> last logged in users
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last command reads list from /var/log/mwtmp
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-> debug and trace
-------------------
strace -p pid
strace -s 200 elffilename to intercept system calls, -s 200 for string length
ltrace elffilename
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-> howto run program in bash and keep it running even when terminal closed
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$ nohup script &
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-> Console screensaver
----------------------------------------
setterm -blank 0 to disable it
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-> at
-----------------------------
at 9:15 playcd
at 9:15 mpg123 *
atq - to list programmed jobs
atrm number to delete automatic job with that number
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-> making patches
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diff -u oldfile.c newfile.c > file.patch
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-> applying patches
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patch file.c file.patch
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-> Change the first occurence of stringA in filename file to stringB and saves it in a new file :)
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sed 's/stringA/StringB/' filename > newfilename
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-> Change all the occurences of stringA to stringB in filename :)
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sed 's/stringA/stringB/g' filename > newfilename
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-> Line count, word count and byte count for the file
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wc file
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-> Compress folder with zip
---------------------------------
zip -r filename.zip folder
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-> Resize image
-----------------------------------
man montage
convert -resize 800x600 original.jpg modified.jpg
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-> Time setup
------------------------
date -s 10/13/00
month, day, year
date -s 07:13:30
To change time without spoling date
date -s "month/day/year" + "%D"
date -s "12:00:00" + "%T"
rdate -p ntp.nasa.gov - show the server date and time
rdate -s ntp.nasa.gov synchronize with that server
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-> adding user to group
-------------------------
gpasswd -a user group
usermod -G group1, group2 user
This one could not work with ldap users
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-> deleting user from a group
------------------------
gpasswd -d user group
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networking
-> slip networking via null modem cable
---------------------------------------
connect-server.sh
#!/bin/bash
slattach -s 115200 -p slip /dev/ttyS0 &
sleep 3s;
ifconfig sl0 192.168.0.2 pointopoint 192.168.0.1
route add -host 192.168.0.1 dev sl0
iptables -t nat -A POSTROUTING -p ALL -s 192.168.0.1/24 -d 0/0 -j MASQUERADE
connect-client.sh
#!/bin/bash
slattach -s 115200 -p slip /dev/ttyS0 &
sleep 3s;
ifconfig sl0 192.168.0.1 pointopoint 192.168.0.2
route add -host 192.168.0.2 dev sl0
route add -net 0.0.0.0/0 dev sl0
rm -rf /etc/resolv.conf
# lycos-europe.am dns server
echo "nameserver 10.37.12.3" >> /etc/resolv.conf
# xternet.am dns servers
#echo "nameserver 83.217.224.37" >> /etc/resolv.conf
#echo "nameserver 83.217.224.35" >> /etc/resolv.conf
#lycos dns route
route add -host 10.37.12.3 dev sl0
#xternet dns route
#route add -host 83.217.224.37 dev sl0
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-> netstat
------------------------
# netstat -lnp --ip will display current running daemons
# netstat --anp --inet
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-> when nfs mount is too long
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mount -t nfs -o nolock
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-> samba mount
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from /etc/fstab
//public/install /network/public/install smbfs
credentials=/etc/samba/credentials/noch,uid=1000,gid=1000,fmask=0644,dmask=0755,workgroup=somedomainname
or worst variant with open password in fstab, not recommended:
//public/films /mnt/samba smbfs
user,rw,iocharset=utf8,uid=500,gid=500,fmask=775,dmask=775,password=yourpassword,username=domainusername,workgroup=domainname,debug=4
0 0
cat /etc/samba/credentials/noch
username=noch
password=IHAVECOOLPASSWORD
from console:
mount -t smbfs //public/films /mnt/samba -o
credentials=/etc/samba/credentials/noch
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-> Secure file copy
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scp /path/to/sourcefile username@server:/path/to/destinationfile
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-> wget howto download a site
-----------------------------------------
wget -rl 4 http://someurl
httrack -P proxy.domain.com:8080 -%f ftp://ftp.simtel.net/pub/simtelnet/msdos/turbopas/*
httrack -mirror http://something.stupid
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X
-> howto configure x server
----------------------------
Xorg -configure
if error then
xorgconfig
in debian: dexconf
in gentoo: mkxf86config
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-> wheel mouse in xorg config:
-----------------------------
Section "InputDevice"
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "ImPS/2"
Option "ZAxisMapping" "4 5"
Option "Buttons" "5"
Option "Device" "/dev/input/mice"
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-> lefthanded mouse
---------------------------
xmodmap -pp
xmodmap -e "pointer = 3 2 1"
or
xmodmap -e "pointer = 3 2 1 4 5"
that depend on your mouse type :)
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-> armenian and russian in plain x without some keyboard switcher
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following lines should work with all xorg x11 servers
setxkbmap "us, am(phonetic)" -option
"grp:alt_shift_toggle,grp_led:scroll"
setxkbmap "us, ru(phonetic)" -option
"grp:alt_shift_toggle,grp_led:scroll"
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Drives
--------------------------------
insert cd
# eject -t
#hdaprm -tT /dev/hda - time benchmark
#hdparm -d 1 /dev/hda - set ultradma access using_dma to 1
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howto assign a label to partition
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man e2label :)
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Multimedia
-> zoran card in redhat/fedora system
--------------------------------
options zr36067 card=1 //card number one is new miro vard like drx
alias char-major-81 zr36067
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-> if you connected your firewire camera, but can't use it with computer
mknod -m 0666 /dev/raw1394 c 171 0
mknod -m 0666 /dev/video1394 c 172 0
-> capturing old standard avi with miro capture board
---------------------------
lavrec -i p -w -f a -d 1 -q 36 -a 16 -r 44100 -l -1 -R l -c 2 -t 100000
-T 1 -n
32 -b 256 -s --use-read --max-file-size 1900
/home/norik/Desktop/%09d.avi
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-> convert to vcd or svcd compliant mpeg file with mencoder
----------------------------
pass one:
mencoder $1 $2 $3 -ofps 25.00 -aid 1 -oac lavc -of mpeg -ovc lavc
-lavcopts
vcodec=mpeg1video:keyint=12:aspect=4/3:mbd=2:acodec=mp2:abitrate=224:vbitrate=1152:vrc_buf_size=327:vrc_maxrate=1152:vpass=1
-vf scale=352:288,expand=352:288 -srate 44100 -o /dev/null
pass two:
mencoder $1 $2 $3 -ofps 25.00 -aid 1 -oac lavc -of mpeg -ovc lavc
-lavcopts
vcodec=mpeg1video:keyint=12:aspect=4/3:mbd=2:acodec=mp2:abitrate=224:vbitrate=1152:vrc_buf_size=327:vrc_maxrate=1152:vpass=2
-vf scale=352:288,expand=352:288 -srate 44100 -o $1.tmp.mpeg
dvb-mplex -t VCD -o $1.mpeg $1.tmp.mpeg
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-> convert to dvd compliant mpeg2 with mjpegtools
-----------------------------
lav2yuv $1 | yuvscaler -O DVD | mpeg2enc -f 8 -q 4 -s -o video_tmp.m2v
lav2wav $1 | mp2enc -v 2 -b 224 -r 48000 -s -o sound_tmp.mp2
mplex -f 8 sound_tmp.mp2 video_tmp.m2v -o $1-dvd.mpg
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-> rebuilding avi file index
-------------------------------------------
mencoder -ovc copy -ni -noodml -forceidx -of avi -noodml -oac pcm
000000001.avi -o 1.avi
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-> writing vcd, svcd, with cdrdao
------------------------------------
vcdimager -t svcd 1.mpg 2.mpg 3.mpg
cdrecord -scanbus
if got 1,0,0
cdrdao write --device 1,0,0 --driver generic-mmc --speed 4 videocd.cue
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-> howto extract mpeg2 file from dvd
--------------------------------------
mencoder dvd:// -ovc copy -oac copy -aid audionumber -sid subtitlenumber -of mpeg -o some.mpg
-> how to start kylix3 under modern linux distributions
-------------------------------
export LD_ASSUME_KERNEL=2.2.5
echo 1 > /proc/sys/vm/legacy_va_layout
startkylix
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-> mpg123
-------------------------------
mpg123 -q /folder/*.mp3 &
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Emulation
-> qemu
$ qemu-img create bb.img 100M
Formating 'bb.img', fmt=raw, size=102400 kB
$ qemu -M pc -hda bb.img -cdrom /home/noch/iso/bluebottle/Aos.iso -boot d -m 64
where -boot d boots from cdrom and -boot c boots from harddisk ;)
qemu networking
make sure you compiled your kernel (2.6) with following options
Device Drivers --->
Network device support --->
Universal TUN/TAP device driver support
Then
mdir -p /dev/net (if not exists)
mknod /dev/net/tun c 10 200
modprobe tun
echo "tun" >> /etc/modules (if debian)
if only root can access tun device then
chgrp users /dev/net/tun
chmod g+w /dev/net/tun
config
ifconfig tun0 192.168.0.1 up
configure your qemu system to have 102.168.0.2 ip address
now routing
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
echo "1" >/proc/sys/net/ipv4/ip_forward
that's all :)
-> reread partition table without reboot :)
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apt-get install parted
# partprobe
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:)
(
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