dos2unix endofline conversion:
- od -t d1 <input.txt >output.txt
- perl -pi -e 's/ / /g' input.txt
whats listening on what ports?
- netstat -nlp
- lsof -i tcp:7100
- fuser -v -n tcp 7100
what kind of ldap-server is running?
- ldapsearch -x -h wiz -b "" -s base "objectclass=*"
force screen blanking in x:
- xset dpms force off
reread a partitionable onthefly
- partprobe or 'blockdev –rereadpt /dev/sda'
runtime lib-path variables:
- LD_RUN_PATH LD_LIBRARY_PATH
backup via ssh/netcat:
- tar cfp - . |(ssh user@host 'cd /dir && tar xfp -')
- on server: nc -l -p | (cd /tmp/backup && tar xfp -) on client: tar cfp - / | nc serverip 2222
drop ssh-publickeyfile:
- (ssh user@remote “mkdir .ssh; cat >.ssh/authorized_keys”) < .ssh/id_rsa.pub
create selfsigned cert (for apache etc.):
openssl req -new > new.cert.csr #Step one - create the key and request openssl rsa -in privkey.pem -out new.cert.key #Step two - remove the passphrase from the key (optional) openssl x509 -in new.cert.csr -out new.cert.cert -req -signkey new.cert.key -days 730 #Step three - convert request into signed cert
show contents of x509-cert:
- openssl x509 -in service.crt -noout -text
what dependencies does an rpm-file have?
- rpm -qRp gcc.rpm
show the top ten of cpu-using processes:
- ps ax -o pid,user,pcpu,comm | sort -k +2 |tail -10
presentationsoftware:
- magicpoint, dia, xfig, kivio, Xy-pic, tgif, inkscape, sodipodi
dump whole networkpackets:
- tcpdump -Xnvs 1500 host 1.2.3.4
install perlmodule:
- perl -MCPAN -e 'install Chocolate::Belgian'
how many percent of system are in use cpu-wise?
- ps aux | nawk '{tot+=$5} ; END { print tot}'
packet forwarding + nat:
- iptables -t nat -A PREROUTING -p tcp –dport 1234 -d 1.2.3.4 -j DNAT –to 2.3.4.5
- iptables -t nat -A POSTROUTING -j MASQUERADE -o eth0 -d 2.3.4.5
create a 7GB sparse-file (uses space only when actually needed):
- dd if=/dev/zero of=xm32_debian.img bs=1 count=1 seek=7G
ssh pubkey restrictions of pubkey-auth onto executing something from an array of allowed comands:
- command="sh -c 'if expr \"${SSH_ORIGINAL_COMMAND}\" : \"^rsync.*--server\" >/dev/null ; then $SSH_ORIGINAL_COMMAND ; else echo REJECTED ; fi'" ssh-rsa..
irc-servers from europe:
- irc.belwue.de
- random.ircd.de
- irc.uni-erlangen.de
- irc.leo.org
usenet provider in germany:
- your isp offering a usenet-server
rescan on linux for scsi/san-luns:
- dmesg|grep scsi # find out the number of the scsi-host in use
- echo "1" > /sys/class/fc_host/hostXYZ/issue_lip # XYZ = number of scsi-host
- echo "- - -" > /sys/class/scsi_host/hostXYZ/scan
ask name-server for versioninfo:
- host -c chaos -t txt version.bind someserver.org
create a pkcs12-cert:
- openssl pkcs12 -export -in newcert.pem -inkey newkey.pem -certfile cacert.pem -name ”[friendly name]” -out namecert.p12
Get cryptstring i.e. for httpasswd:
- perl -we 'print crypt("secret",int(rand(90))+10),"\n";'
OpenSwan cvs checkout:
- cvs -d :pserver:anoncvs@anoncvs.openswan.org:/public/cvs login # pass anoncvs
- cvs -d :pserver:anoncvs@anoncvs.openswan.org:/public/cvs co openswan-2
change cdrom in qemu virtualmachine
- <ctrl+alt+2>, eject cdrom, change cdrom /path/cd.iso, <ctrl+alt+1>
vmware config for shared disks (for testing clusterstuff)
create preallocated disk (not this spare thingy), use new scsi-bus (i.e. target 1.1 for shared disk), add options to vm-configfile.vmx: scsi1.sharedBus = "virtual" disk.locking = "false" diskLib.dataCacheMaxSize = "0"
linux cpu-speed tuning
- echo ondemand >/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
running slrn on my utf8-debian
LANG=en_GB.iso88591 luit -encoding ISO-8859-1 slrn -h news.individual.de
getting a remote firefox on 'ssh -X' shell
firefox -no-remote
setting rpm-queryformat to also see architecture of rpms by default
echo "%_query_all_fmt %%{name}-%%{version}-%%{release}.%%{arch}" >~/.rpmmacros
sendmail: disable dns-usage for smarthost
echo 'hosts files' >/etc/mail/service.switch echo 'aliases files' >>/etc/mail/service.switch echo '1.2.3.4 mailgw' >>/etc/hosts vi sendmail.cf # set 'DSmailgw' echo 'O ServiceSwitchFile=/etc/mail/service.switch' >>/etc/mail/sendmail.cf echo 'O HostsFile=/etc/hosts' >>/etc/mail/sendmail.cf
