Update file that already exists in tar archive
[root@james ~]# tar -uvf ./test.tar updatefile
Append file that doesnt not exist to archive.
[root@james ~]# tar -rvf ./test.tar newfilesfile
Extract one file from archive.
[root@james ~]# tar -xvf ./test.tar somefile
Search for a package
apt-cache search <phrase>
Install a package
apt-get install <package>
Upgrade kernel
apt-get dist-upgrade
Create a new file using touch and modify its access time.
Set the date to Feb 1st, 2009 @ 730am.
[root@stone backups]# touch testfile2 -t 200902010730 testfile2
Add rule
root@firefly:/data/music# ufw allow from 10.200.80.132 to any port 3689
Delete rule by line number.
root@firefly:/data/music# ufw delete 1
Deleting:
allow 3689
Proceed with operation (y|n)? y
Rule deleted
View current rules
root@firefly:/data/music# ufw status
Status: active
To Action From
– —— —-
22 ALLOW Anywhere
21 ALLOW Anywhere
3689 ALLOW 10.200.80.132
#!/usr/bin/python
def main():
salary1 = input(”Enter Salary #1: “)
salary2 = input(”Enter Salary #2: “)
# SET GLOBAL TO SHARE VARS
global x
global y
if(salary1 < salary2):
x=salary1
y=salary2
else:
y=salary1
x=salary2
def make_percent():
global total
total = 100-(float(x)/float(y)*100)
total=int(round(total,0))
print “Total Difference:”,total,”%”
main()
make_percent()
root@donkey:~/tech/core# python calc_number_diff.py
Enter Salary #1: 75
Enter Salary #2: 76
Total Difference: 1 %
Install packages
apt-get install lvm2 dmsetup mdadm reiserfsprogs xfsprogs
Create partitions
fdisk /dev/sda
-create new partition (’n')
-change system partition type to lvm (’t')
-enter ‘8e’ for hex partition type
-write partition table to disk (’w')
Create physical volume
root@backupserv:~# pvcreate /dev/sdb1 /dev/sda2 /dev/sdc1
Can’t open /dev/sdb1 exclusively. Mounted filesystem?
Wiping software RAID md superblock on /dev/sda2
Physical volume “/dev/sda2″ successfully created
Wiping software RAID md superblock on /dev/sdc1
Physical volume “/dev/sdc1″ successfully created
root@backupserv:~# pvdisplay
“/dev/sda2″ is a new physical volume of “903.57 GB”
— NEW Physical volume —
PV Name /dev/sda2
VG Name
PV Size 903.57 GB
Allocatable NO
PE Size (KByte) 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID zsP1EO-SlwB-nryo-gEP7-fInc-hJc4-ytVpLX
“/dev/sdc1″ is a new physical volume of “931.51 GB”
— NEW Physical volume —
PV Name /dev/sdc1
VG Name
PV Size 931.51 GB
Allocatable NO
PE Size (KByte) 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID V3RZ2b-FBsM-HoI6-aQED-ouu9-LpR1-m02VLO
Create a Volume Group
root@backupserv:~# vgcreate data /dev/sdc1 /dev/sda2
Volume group “data” successfully created
root@backupserv:~# vgdisplay
— Volume group —
VG Name data
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 1
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 2
Act PV 2
VG Size 1.79 TB
PE Size 4.00 MB
Total PE 469780
Alloc PE / Size 0 / 0
Free PE / Size 469780 / 1.79 TB
VG UUID XJVXrA-m5xO-GARp-6WT0-JFlX-7ARj-jxJChV
root@backupserv:~# vgscan
Reading all physical volumes. This may take a while…
Found volume group “data” using metadata type lvm2fdisk /dev/sda
Create Logical Volume
root@backupserv:~# lvcreate –name share1 –size 100G data
Logical volume “share1″ created
root@backupserv:~# lvcreate –name share2 –size 500G data
Logical volume “share2″ created
*run lvscan for new logical volume scan.
Format partition
root@backupserv:~# mkfs.ext3 /dev/data/share1
mke2fs 1.41.9 (22-Aug-2009)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
6553600 inodes, 26214400 blocks
1310720 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=0
800 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872
Writing inode tables: 192/800
Mount device
root@backupserv:~# mkdir /mnt/share2
root@backupserv:~# mount /dev/data/share2 /mnt/share2
/dev/mapper/data-share2
516061624 202652 489644572 1% /mnt/share2
Deleting an Volume Group
root@backupserv:~# vgremove data
Do you really want to remove volume group “data” containing 2 logical volumes? [y/n]: yes
Can’t remove open logical volume “share1″
root@backupserv:~# umount /mnt/share*
root@backupserv:~# vgremove data
Do you really want to remove volume group “data” containing 2 logical volumes? [y/n]: yes
Do you really want to remove active logical volume “share1″? [y/n]: yes
Logical volume “share1″ successfully removed
Do you really want to remove active logical volume “share2″? [y/n]: yes
Logical volume “share2″ successfully removed
Volume group “data” successfully removed
Delete Physical Volume
root@backupserv:~# pvremove /dev/sdc1 /dev/sdb1
Labels on physical volume “/dev/sdc1″ successfully wiped
Physical Volume /dev/sdb1 not found
ref: http://www.howtoforge.com/linux_lvm_p2
Adding Additional Disk to LVM
create fdisk LVM partition first….
root@backupserv:~# pvcreate /dev/sdb1
Physical volume “/dev/sdb1″ successfully created
root@backupserv:~# vgextend vol1 /dev/sdb1
Volume group “vol1″ successfully extended
root@backupserv:~# vgdisplay vol1
— Volume group —
VG Name vol1
System ID
Format lvm2
Metadata Areas 3
Metadata Sequence No 5
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 3
Act PV 3
VG Size 2.70 TB
PE Size 4.00 MB
Total PE 708246
Alloc PE / Size 469238 / 1.79 TB
Free PE / Size 239008 / 933.62 GB
VG UUID RS2K3i-SOJ8-a230-fcQL-8PX0-Bpuj-qSUYKz
root@backupserv:~# lvextend -L +930G /dev/vol1/data1 /dev/sdb1
Extending logical volume data1 to 2.70 TB
Logical volume data1 successfully resized
root@backupserv:~# resize2fs /dev/vol1/data1
resize2fs 1.41.9 (22-Aug-2009)
Filesystem at /dev/vol1/data1 is mounted on /mnt/data; on-line resizing required
old desc_blocks = 115, new_desc_blocks = 173
….
*watch more space become available with ‘watch df -h’
‘-exec’ using trailing ‘\’
[root@monk ~]# tar -cvf test.tar install.log
install.log
[root@monk ~]# time find /tmp/conf-2-xp -name *.xad -exec tar –append –file=/root/test.tar {} +;
find: /tmp/conf-2-xp/9a2f6257887d6e51f58ce2/amd64: Permission denied
find: /tmp/conf-2-xp/9a2f6257887d6e51f58ce2/i386: Permission denied
find: /tmp/conf-2-xp/System Volume Information: Permission denied
tar: Removing leading `/’ from member names
real 0m15.239s
user 0m0.464s
sys 0m2.628s
[root@monk ~]# du -h test.tar
310M test.tar
[root@monk ~]# rm -f test.tar
*delete fiel and recreate since we are appending and comparing file size after each run.
‘-exec’ using trailing ‘+’
[root@monk ~]# tar -cvf test.tar install.log
install.log
[root@monk ~]# time find /tmp/conf-2-xp -name *.xad -exec tar –append –file=/root/test.tar {} \;
find: /tmp/conf-2-xp/9a2f6257887d6e51f58ce2/amd64: Permission denied
find: /tmp/conf-2-xp/9a2f6257887d6e51f58ce2/i386: Permission denied
…
real 0m39.015s
user 0m2.739s
sys 0m21.893s
[root@monk ~]# du -h test.tar
310M test.tar
Using xargs.
*use -print0 option to prevent whitespace issue. ‘xargs -0′ passes first argument.
[root@monk ~]# rm test.tar
rm: remove regular file `test.tar’? yes
[root@monk ~]# tar -cvf test.tar install.log
install.log
[root@monk ~]# time find /tmp/conf-2-xp -name ‘*.xad’ -print0 | xargs -0 tar –append –file=/root/test.tar;
find: /tmp/conf-2-xp/9a2f6257887d6e51f58ce2/amd64: Permission denied
find: /tmp/conf-2-xp/9a2f6257887d6e51f58ce2/i386: Permission denied
find: /tmp/conf-2-xp/System Volume Information: Permission denied
tar: Removing leading `/’ from member names
real 0m15.073s
user 0m0.446s
sys 0m2.774s
[root@monk ~]# du -h test.tar
310M test.tar
Result: Using ‘+’ is two times faster than using ‘\’. -exec and xargs are about the same speed, when using ‘+’ for -exec.
Enabling Caching
*verify caching is on. if need to update, then restart.
jesterj@jesterj-laptop:/etc/mysql$ grep "query" /etc/mysql/my.cnf
query_cache-type = 1 #cache everything
query_cache_limit = 1M
query_cache_size = 16M
*Note that variables in the my.cnf file are reflecteed in the below variables.
mysql> SHOW VARIABLES LIKE '%query_cache%';
+------------------------------+----------+
| Variable_name | Value |
+------------------------------+----------+
| have_query_cache | YES |
| query_cache_limit | 1048576 |
| query_cache_min_res_unit | 4096 |
| query_cache_size | 16777216 |
| query_cache_type | ON |
| query_cache_wlock_invalidate | OFF |
+------------------------------+----------+
6 rows in set (0.00 sec)
View the query cache
mysql> SHOW STATUS LIKE '%qcache%';
+-------------------------+----------+
| Variable_name | Value |
+-------------------------+----------+
| Qcache_free_blocks | 1 |
| Qcache_free_memory | 16612448 |
| Qcache_hits | 1 |
| Qcache_inserts | 2 |
| Qcache_lowmem_prunes | 0 |
| Qcache_not_cached | 110 |
| Qcache_queries_in_cache | 2 |
| Qcache_total_blocks | 6 |
+-------------------------+----------+
8 rows in set (0.00 sec)
Now run test queries for a database so we can test query cache..
mysql> select * from test.data order by name ASC
mysql> select * from test.data order by name DESC
Notice as you run more and more queries the available free memory descreases and the queries in cache number increases
mysql> SHOW STATUS LIKE '%qcache%';
+-------------------------+----------+
| Variable_name | Value |
+-------------------------+----------+
| Qcache_free_blocks | 1 |
| Qcache_free_memory | 16534728 |
| Qcache_hits | 5 |
| Qcache_inserts | 3 |
| Qcache_lowmem_prunes | 0 |
| Qcache_not_cached | 110 |
| Qcache_queries_in_cache | 3 |
| Qcache_total_blocks | 8 |
+-------------------------+----------+
8 rows in set (0.00 sec)
Demand Query Caching
You can also specify query cache on demand so only queries that you specify
are cached.
Change query cache type to 2.
[mysql]
….
query-cache-type = 2
….
Restart mysql.
sudo /etc/init.d/mysql restart
Now log back into mysql and verify that DEMAND caching is set
mysql> SHOW VARIABLES LIKE '%query_cache%';
+------------------------------+----------+
| Variable_name | Value |
+------------------------------+----------+
| have_query_cache | YES |
| query_cache_limit | 1048576 |
| query_cache_min_res_unit | 4096 |
| query_cache_size | 16777216 |
| query_cache_type | DEMAND |
| query_cache_wlock_invalidate | OFF |
+------------------------------+----------+
6 rows in set (0.00 sec)
Now specify SQL_CACHE when you run a statemnt.
mysql> select SQL_CACHE * from test.data order by name ASC
Note that you can also use SQL_NO_CACHE when query-cache-type=1 to turn off caching for a particular sql stmt.
Create the procedure.
mysql> CREATE PROCEDURE donkey() SELECT * FROM data WHERE name LIKE '%64%';
Query OK, 0 rows affected (0.00 sec)
Execute the procedure.
mysql> CALL donkey();
+-----+------------+
| id | name |
+-----+------------+
| 31 | 1265397164 |
| 99 | 1265402640 |
| 100 | 1265402641 |
| 101 | 1265402642 |
| 102 | 1265402643 |
| 103 | 1265402644 |
| 104 | 1265402645 |
| 105 | 1265402646 |
| 106 | 1265402647 |
| 107 | 1265402648 |
| 108 | 1265402649 |
| 122 | 1265402664 |
| 219 | 1265402764 |
| 316 | 1265402864 |
| 479 | 1265404564 |
| 553 | 1265404640 |
| 554 | 1265404641 |
| 555 | 1265404642 |
| 556 | 1265404643 |
+-----+------------+
19 rows in set (0.00 sec)
Display the query.
mysql> SHOW CREATE PROCEDURE donkey2\G;
*************************** 1. row ***************************
Procedure: donkey2
sql_mode:
Create Procedure: CREATE DEFINER=`root`@`localhost` PROCEDURE `donkey2`()
SELECT * FROM data WHERE name LIKE '%3%'
character_set_client: latin1
collation_connection: latin1_swedish_ci
Database Collation: latin1_swedish_ci
1 row in set (0.00 sec)
ERROR:
No query specified
Delete the procedure.
mysql> DROP PROCEDURE donkey;
Query OK, 0 rows affected (0.00 sec)
The following is an overview of how to edit standard files, the directory structure and how to enable site features in apache2. Let’s first dig into the folders that comprise apache2.
Files
$tree -d /etc/apache2 #only show dirs
/etc/apache2/
|– conf.d
|– mods-available
|– mods-enabled
|– sites-available
`– sites-enabled
Let’s define the functions of each.
conf.d - configuration files for modules, etc.
mods-available - list of available modules for apache
mods-enabled - list of modules that are loaded into apache config
site-available - configuration files for virtual hosts
sites-enabled - ?
Files also listed in /etc/apache2…
|– apache2.conf
|– envvars
|– httpd.conf
|– magic
`– ports.conf
Enabling and Disabling Modules
First, check the available modules on your system.
/etc/apache2/mods-available/
|– actions.conf
|– actions.load
|– alias.conf
|– alias.load
|– asis.load
|– auth_basic.load
|– auth_digest.load
|– authn_alias.load
|– authn_anon.load
|– authn_dbd.load
…..
To view all mods enabled view the mods-enabled dir. Note that these are sym linked to the mods-avialable directory.
/etc/apache2/mods-enabled
|– alias.conf -> ../mods-available/alias.conf
|– alias.load -> ../mods-available/alias.load
|– auth_basic.load -> ../mods-available/auth_basic.load
|– authn_file.load -> ../mods-available/authn_file.load
|– authz_default.load -> ../mods-available/authz_default.load
|– authz_groupfile.load -> ../mods-available/authz_groupfile.load
…
Let’s say we want to enable ‘mod-security’. The best way to do this on ubuntu/debian is to use ‘a2enmod’ utility, which stands for apache2 enable module.
jesterj@jesterj-laptop:/etc/apache2$ sudo a2enmod ssl
Enabling module ssl.
See /usr/share/doc/apache2.2-common/README.Debian.gz on how to configure SSL and create self-signed certificates.
Run '/etc/init.d/apache2 restart' to activate new configuration!
Note: You can also just type ‘a2enmod’ to list all available modules.
Now restart apache.
jesterj@jesterj-laptop:/etc/apache2$ sudo /etc/init.d/apache2 restart
* Restarting web server apache2 ... waiting [ OK ]
Now, verify the module is available.
jesterj@jesterj-laptop:/etc/apache2$ ls -la /etc/apache2/mods-enabled/ | grep ssl
lrwxrwxrwx 1 root root 26 2010-02-08 19:20 ssl.conf -> ../mods-available/ssl.conf
lrwxrwxrwx 1 root root 26 2010-02-08 19:20 ssl.load -> ../mods-available/ssl.load
To disable a module, do the same thing but use ‘a2dismod’.
Configuring Sites