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how_to [2012/03/23 19:26] – [ramfs on Linux] k2patelhow_to [2020/08/10 02:35] (current) – external edit 127.0.0.1
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 To drop all the table in the mysql database - use the following command. To drop all the table in the mysql database - use the following command.
 +<WRAP prewrap>
 <code mysql> <code mysql>
 mysqldump -u[USERNAME] -p[PASSWORD] --add-drop-table --no-data [DATABASE] | grep ^DROP | mysql -u[USERNAME] -p[PASSWORD] [DATABASE] mysqldump -u[USERNAME] -p[PASSWORD] --add-drop-table --no-data [DATABASE] | grep ^DROP | mysql -u[USERNAME] -p[PASSWORD] [DATABASE]
 </code> </code>
 +</WRAP>
  
 ==== How to list pear using php ==== ==== How to list pear using php ====
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 </code> </code>
  
 +
 +==== Force Change password next login ====
 +
 +<code bash>
 +chage -d 0 <Username>
 +</code>
 ==== Setting up Multiple ip using single file ==== ==== Setting up Multiple ip using single file ====
  
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 If you need to run cron with your own php.ini and send result to mail use following. If you need to run cron with your own php.ini and send result to mail use following.
 +<WRAP prewrap>
 <code bash> <code bash>
 */1 */2 * * * /usr/local/bin/php --php-ini /srv/www/conf/php.ini /srv/www/public_html/cron.php | /usr/bin/mail -s "Output of crontab" xyz@yahoo.com */1 */2 * * * /usr/local/bin/php --php-ini /srv/www/conf/php.ini /srv/www/public_html/cron.php | /usr/bin/mail -s "Output of crontab" xyz@yahoo.com
 </code> </code>
 +</WRAP>
 ==== Exit Codes ==== ==== Exit Codes ====
 At some point you feel like there is no exit code documentation and you want find you what should it return.\\ At some point you feel like there is no exit code documentation and you want find you what should it return.\\
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 </code> </code>
  
 +Redhat / Fedora
 +NM looks for /etc/dhclient-<interface>.conf then /etc/dhcp/dhclient-<interface>.conf \\
 +and will merge the first found into the dhclient config files it produces.
 ==== Enable port below 1024 for all users ==== ==== Enable port below 1024 for all users ====
  
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 **Step 2** : Create Raid Drive. ( this command will create "/dev/md10" ) **Step 2** : Create Raid Drive. ( this command will create "/dev/md10" )
 +<WRAP prewrap>
 <code bash> <code bash>
 mdadm --create --level=10 --raid-devices=4 --spare-devices=0 --chunk=128 --layout=f2 /dev/md10 /dev/sdf1 /dev/sdg1 /dev/sdh1 /dev/sdi1 mdadm --create --level=10 --raid-devices=4 --spare-devices=0 --chunk=128 --layout=f2 /dev/md10 /dev/sdf1 /dev/sdg1 /dev/sdh1 /dev/sdi1
 </code> </code>
 +</WRAP>
  
 **Step 3**: Format Drive ( I am formatting for XFS )  **Step 3**: Format Drive ( I am formatting for XFS ) 
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 <code bash> <code bash>
 mount -t ramfs none /tmp/toall mount -t ramfs none /tmp/toall
 +</code>
 +
 +==== Reduce default tmpfs size ====
 +Default size of **/dev/shm** is almost 50% of your memory.\\
 +In order to reduce it to some optimal value you can update your /etc/fstab.\\
 +just add size variable in your option field : comma saperated : will do.
 +
 +<code bash>
 +tmpfs                   /dev/shm                tmpfs   defaults,size=8g        0 0
 +</code>
 +
 +
 +==== Password Hashing Algorithm ====
 +
 +=== Display Hashing Algorithm on server ===
 +
 +<code bash>
 +authconfig --test | grep hashing
 +</code>
 +
 +=== Change Algorithm on server ===
 +
 +<code bash>
 +authconfig --passalgo=sha512 --update
 +</code>
 +
 +==== Changing encrypted file system password ====
 +
 +If you have encrypted partitions you can change password using following commands.
 +
 +<note warning>Replace sda2 with your drive number</note>
 +
 +=== Check which key slot is occupied ===
 +
 +<code bash>
 +cryptsetup luksDump /dev/sda2
 +</code>
 +
 +=== Now add key to next free slot ===
 +
 +<code bash>
 +cryptsetup luksAddKey /dev/sda2
 +</code>
 +
 +=== Now remove / Disable Previous slot ===
 +
 +<code bash>
 +cryptsetup luksKillSlot /dev/sda2 0
 +</code>
 +
 +==== Check for Operation Windigo infection ====
 +<code bash>
 +ssh -G 2>&1 | grep -e illegal -e unknown > /dev/null && echo “System clean” || echo “System infected”
 +</code>
 +[[http://news.softpedia.com/news/quot-Operation-Windigo-quot-Attack-Infects-10-000-Unix-Servers-Millions-of-PCs-at-Risk-432920.shtml?utm_source=dlvr.it&utm_medium=twitter|Ref.]]
 +
 +==== Creating patch for rpm ====
 +this can be used as '%patch0 -p1 -b <file_name>'
 +<code bash>
 +diff -ru hdf-4.2.12-orig hdf-4.2.12-diff >| ../SOURCES/hdf-4.2.12.example.patch
 +</code>
 +
 +==== Configure option for Fedora / Redhat ====
 +replace amaya with your application etc...\\
 +This is usefull while compiling sources for systems
 +<WRAP prewrap>
 +<code bash>
 +../configure -enable-system-raptor '--build=x86_64-redhat-linux-gnu' '--host=x86_64-redhat-linux-gnu' '--program-prefix=' '--prefix=/usr' '--exec-prefix=/usr' '--bindir=/usr/bin' '--sbindir=/usr/sbin' '--sysconfdir=/etc' '--datadir=/usr/share' '--includedir=/usr/include' '--libdir=/usr/lib64' '--libexecdir=/usr/libexec' '--sharedstatedir=/var/lib' '--mandir=/usr/share/man' '--infodir=/usr/share/info' '--exec_prefix=/usr' 'build_alias=x86_64-redhat-linux-gnu' 'host_alias=x86_64-redhat-linux-gnu' '--libexecdir=/usr/lib64/amaya' '--localstatedir=/var' '--datadir=/usr/share/amaya' '--sysconfdir=/etc/amaya' '--with-logdir=$(localstatedir)/log/amaya' '--with-pidfile=$(localstatedir)/run/amaya.pid'
 +</code>
 +</WRAP>
 +
 +==== Run single command parallel'y with diff values ====
 +<WRAP prewrap>
 +<code bash>
 +(echo "http://test.k2patel.in"; echo "http://test.ornl.gov"; echo "http://yahoo.com" ) | parallel 'ab -n 50 -c 50 {}'
 +</code>
 +</WRAP>
 +
 +==== Print yum variable value ====
 +<code python>
 +import yum
 +import pprint 
 +
 +yvar = yum.YumBase()
 +pprint.pprint(yvar.conf.yumvar, width=1)
 +</code>
 +
 +==== Disable Predictable interface name in RHEL / CentOS ====
 +Pass following during boot kernel command line.
 +<code bash>
 +net.ifnames=0
 </code> </code>
how_to.1332530794.txt.gz · Last modified: 2020/08/10 02:30 (external edit)