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May 15 / 2017
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Linux

Remove list of mail addresses from postfix queue

There is no easy way to remove a list of mails in queue with a same sender or domain in Postfix. But you can use some standard commands to get this working.

First check the list of mails you want to remove with something like

postqueue -p |grep -e 'john.doe@domain.com\|jon.doe@domain.com\|john.do@domain.com' -B2 |grep "^[A-Z0-9]"

1	postqueue -p \|grep -e '[email protected]\\|[email protected]\\|[email protected]' -B2 \|grep "^[A-Z0-9]"

You’re getting the list of mails that you will remove with the sender

FC0177DF1A0     8373 Thu May  6 11:24:56  sender@mywebsite.com
F179A2C68AB     9469 Sun May  7 03:21:41  sender@mywebsite.com
EAE217FB850    11049 Sat May  8 04:20:32  sender@mywebsite.com

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FC0177DF1A0 8373 Thu May 6 11:24:56 sender@mywebsite.com

F179A2C68AB 9469 Sun May 7 03:21:41 sender@mywebsite.com

EAE217FB850 11049 Sat May 8 04:20:32 sender@mywebsite.com

And now you can remove those mails from the queue by using postsuper -d

postqueue -p |grep -e 'john.doe@domain.com\|jon.doe@domain.com\|john.do@domain.com' -B2 |grep "^[A-Z0-9]\{10\}" |cut -d" " -f1 |postsuper -d -

1	postqueue -p \|grep -e '[email protected]\\|[email protected]\\|[email protected]' -B2 \|grep "^[A-Z0-9]\{10\}" \|cut -d" " -f1 \|postsuper -d -

You will see the mails being removed

postsuper: FC0177DF1A0: removed
postsuper: F179A2C68AB: removed
postsuper: EAE217FB850: removed
postsuper: Deleted: 3 messages

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postsuper: FC0177DF1A0: removed

postsuper: F179A2C68AB: removed

postsuper: EAE217FB850: removed

postsuper: Deleted: 3 messages

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May 04 / 2017
0

Linux

Reduce partition size on EXT filesystems on Linux

It is possible to modify a partition size on EXT filesystem thanks to some few commands.

We will take here a simple example:

We have a /dev/sda5 partition mounted on /home
Its size is currently 150G and we want to reduce it to 100G

Let’s check the current config (mounting point and size):

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1        28G  3.3G   23G   8% /
/dev/sda2       477M  112M  341M  25% /boot
/dev/sda3       4.7G   12M  4.5G   1% /tmp
/dev/sda4        32G  470M   30G   2% /var
/dev/sda5       148G   87M  140G   1% /home

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Filesystem Size Used Avail Use% Mounted on

/dev/sda1 28G 3.3G 23G 8% /

/dev/sda2 477M 112M 341M 25% /boot

/dev/sda3 4.7G 12M 4.5G 1% /tmp

/dev/sda4 32G 470M 30G 2% /var

/dev/sda5 148G 87M 140G 1% /home

We need to first unmount the partition:

# umount /dev/sda5

1	# umount /dev/sda5

If you can’t unmount it, double check what process is using it with the lsof command:

# lsof /home

1	# lsof /home

Then proceed with a check with e2fsck command and resize the partition with resize2fs by defining the new size (M for Megabytes, G for Gigabytes, and so on…)

# e2fsck -f /dev/sda5
# resize2fs /dev/sda5 100G

1 2	# e2fsck -f /dev/sda5 # resize2fs /dev/sda5 100G

Mount your partition back to your system:

# mount /home

1	# mount /home

And check again your partition sizes :

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1        28G  3.3G   23G   8% /
/dev/sda2       477M  112M  341M  25% /boot
/dev/sda3       4.7G   12M  4.5G   1% /tmp
/dev/sda4        32G  470M   30G   2% /var
/dev/sda5        99G   87M   94G   1% /home

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Filesystem Size Used Avail Use% Mounted on

/dev/sda1 28G 3.3G 23G 8% /

/dev/sda2 477M 112M 341M 25% /boot

/dev/sda3 4.7G 12M 4.5G 1% /tmp

/dev/sda4 32G 470M 30G 2% /var

/dev/sda5 99G 87M 94G 1% /home

We can see that the partition /home has now a size of 100G as expected!

Apr 24 / 2017
0

Linux

Find ILO IP on a HP server with Linux

If you forgot what iLO IP has been defined on your linux server and you are working remotely on it, don’t worry, you can still retrieve it with a common tool called ipmitool – available on most of the distros with standard packages:

[admin@myserver /]# ipmitool lan print
Set in Progress : Set Complete
Auth Type Support :
Auth Type Enable : Callback :
: User :
: Operator :
: Admin :
: OEM :
IP Address Source : Static Address
IP Address : 10.10.50.20
Subnet Mask : 255.255.255.0
MAC Address : 1a:2b:3c:4d:56:78
SNMP Community String :
BMC ARP Control : ARP Responses Enabled, Gratuitous ARP Disabled
Default Gateway IP : 10.10.50.254
802.1q VLAN ID : Disabled
802.1q VLAN Priority : 0
RMCP+ Cipher Suites : 0,1,2,3
Cipher Suite Priv Max : XuuaXXXXXXXXXXX
: X=Cipher Suite Unused
: c=CALLBACK
: u=USER
: o=OPERATOR
: a=ADMIN
: O=OEM

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[admin@myserver /]# ipmitool lan print

Set in Progress : Set Complete

Auth Type Support :

Auth Type Enable : Callback :

: User :

: Operator :

: Admin :

: OEM :

IP Address Source : Static Address

IP Address : 10.10.50.20

Subnet Mask : 255.255.255.0

MAC Address : 1a:2b:3c:4d:56:78

SNMP Community String :

BMC ARP Control : ARP Responses Enabled, Gratuitous ARP Disabled

Default Gateway IP : 10.10.50.254

802.1q VLAN ID : Disabled

802.1q VLAN Priority : 0

RMCP+ Cipher Suites : 0,1,2,3

Cipher Suite Priv Max : XuuaXXXXXXXXXXX

: X=Cipher Suite Unused

: c=CALLBACK

: u=USER

: o=OPERATOR

: a=ADMIN

: O=OEM

If you’re getting such an error when you are using the command:

[admin@myserver /]# ipmitool lan print
Could not open device at /dev/ipmi0 or /dev/ipmi/0 or /dev/ipmidev/0: No such file or directory

1 2	[admin@myserver /]# ipmitool lan print Could not open device at /dev/ipmi0 or /dev/ipmi/0 or /dev/ipmidev/0: No such file or directory

This means you just need to enable some modules before:

[admin@myserver /]# modprobe ipmi_devintf
[admin@myserver /]# modprobe ipmi_si

1 2	[admin@myserver /]# modprobe ipmi_devintf [admin@myserver /]# modprobe ipmi_si

Apr 13 / 2017
0

Linux

Quit telnet – Escape character

Stuck with a telnet session that refuses to give you hand back on console?
No worries… You just have to know the correct command to sort this out!

When you are opening a telnet connection, you probably got something like:

user@server# telnet 127.0.0.1 80
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.

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user@server# telnet 127.0.0.1 80

Trying 127.0.0.1...

Connected to 127.0.0.1.

Escape character is '^]'.

So, if you want to quit, you just have to use the “escape character” as indicated. But this character is not designed to be typed with 2 characters like “^” and then “]” – you have to use a direct command that can be different depending on your OS:

Windows: Ctrl + $
Linux: Ctrl + Alt Gr + ]
Mac OS: Ctrl + $

And press Enter once you inserted this escape character so you can get the standard telnet prompt and be able to type quit to exit the prompt.

This will result in a command like:

^]
telnet> quit
Connection closed.
user@server#

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^]

telnet> quit

Connection closed.

user@server#

And here you go – you’re out of telnet 🙂 !

Apr 07 / 2017
0

Linux

Display time with history command

When you are using the history command on a UNIX system, by default, you’re only getting an action list with numbers but no date and/or time to complete this history. For that, you have to define an environment variable HISTTIMEFORMAT that will describe how you want to display the timestamp for each command.

To display the timestamp temporarily (during session), you can just export the variable before sending the command:

$export HISTTIMEFORMAT="%d/%m/%y %T " ; history

1	$export HISTTIMEFORMAT="%d/%m/%y %T " ; history

You will get:

2021  01/04/17 11:54:04 systemctl list-units
2022  01/04/17 11:54:10 systemctl list-unit-files
2023  01/04/17 11:54:15 cd /etc/
2024  01/04/17 11:54:33 ls -lsta
2025  01/04/17 11:54:33 ps auxw | grep apache
2026  01/04/17 11:54:35 date
2027  01/04/17 11:54:35 cd ..
2028  01/04/17 11:54:37 cd /var/log
2029  01/04/17 11:54:37 ls -lsta
2030  01/04/17 11:54:40 cat messages
2031  01/04/17 15:48:44 history
2032  01/04/17 15:48:51 export HISTTIMEFORMAT="%d/%m/%y %T " ; history

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2021 01/04/17 11:54:04 systemctl list-units

2022 01/04/17 11:54:10 systemctl list-unit-files

2023 01/04/17 11:54:15 cd /etc/

2024 01/04/17 11:54:33 ls -lsta

2025 01/04/17 11:54:33 ps auxw | grep apache

2026 01/04/17 11:54:35 date

2027 01/04/17 11:54:35 cd ..

2028 01/04/17 11:54:37 cd /var/log

2029 01/04/17 11:54:37 ls -lsta

2030 01/04/17 11:54:40 cat messages

2031 01/04/17 15:48:44 history

2032 01/04/17 15:48:51 export HISTTIMEFORMAT="%d/%m/%y %T " ; history

If you want to keep that display for a future session, you have to add this variable to your bash profile and reload your profile:

$echo 'export HISTTIMEFORMAT="%d/%m/%y %T "' >> ~/.bash_profile
$source ~/.bash_profile

1 2	$echo 'export HISTTIMEFORMAT="%d/%m/%y %T "' >> ~/.bash_profile $source ~/.bash_profile

Mar 29 / 2017
0

Uncategorized

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