Posts Tagged ‘cat’
Tuesday, November 22nd, 2011 In order to debug some PHP session problems on Debian, I needed to check the count of existing session files.
When PHP is compiled from source usually, by default sessions are stored in /tmp directory, however this is not the case on Debian.
Debian’s PHP session directory is different, there the sessions are stored in the directory:
/var/lib/php5
I’ve discovered the session directory location by reading Debian’s cron shell script, which delete session files on every 30 minutes.
Here is the file content:
debian~# cat /etc/cron.d/php5
# /etc/cron.d/php5: crontab fragment for php5
# This purges session files older than X, where X is defined in seconds
# as the largest value of session.gc_maxlifetime from all your php.ini
# files, or 24 minutes if not defined. See /usr/lib/php5/maxlifetime
# Look for and purge old sessions every 30 minutes
09,39 * * * * root [ -x /usr/lib/php5/maxlifetime ] &&
[ -d /var/lib/php5 ] && find /var/lib/php5/ -type f -cmin +$(/usr/lib/php5/maxlifetime) -delete
To check the amount of existing PHP opened session files:
debian:~# ls -1 /var/lib/php5|wc -l
14049
Tags: amount, amp, apache, cat, check, count, cron, crontab, Debian, debian gnu, DEBUG, directory location, file, fragment, gnu linux, ini files, lib, Linux, linux apache, location, maxlifetime, order, php session, purges, root, session directory, session files, sessions, Shell, shell script, tmp, type, usr, value, var
Posted in Linux, System Administration, Various | No Comments »
Tuesday, August 2nd, 2011 
Today I’ve learned from a admin colleague, a handy tip.
I’m administrating some Linux servers which are configured on purpose not to run on the default ssh port number (22) and therefore each time I connect to a host I have to invoke the ssh command with -p PORT_NUMBER option.
This is not such a problem, however when one has to administrate a dozen of servers each of which is configured to listen for ssh connections on various port numbers, every now and then I had to check in my notes which was the correct ssh port number I’m supposed to connect to.
To get around this silly annoyance the ssh client has a feature, whether a number of ssh server hosts can be preconfigured from the ~/.ssh/config in order to later automatically recognize the port number to which the corresponding host will be connecting (whenever) using the ssh user@somehost without any -p argument specified.
In order to make the “auto detection” of the ssh port number, the ~/.ssh/config file should look something similar to:
hipo@noah:~$ cat ~/.ssh/config
Host home.*.www.pc-freak.net
User root
Port 2020
Host www.remotesystemadministration.com
User root
Port 1212
Host sub.www.pc-freak.net
User root
Port 2222
Host www.example-server-host.com
User root
Port 1234
The *.www.pc-freak.net specifies that all ssh-able subdomains belonging to my domain www.pc-freak.net should be by default sshed to port 2020
Now I can simply use:
hipo@noah:~$ ssh root@myhosts.com
And I can connect without bothering to remember port numbers or dig into an old notes.
Hope this ssh tip is helpful.
Tags: administrate, annoyance, auto detection, cat, client, com, configHost, domain pc, example server, file, freak, handy tip, home, linux servers, net, noah, number 22, number option, order, port, port 22, port numbers, purpose, remotesystemadministration, root, root port, server host, server hosts, somehost, ssh, ssh client, ssh command, ssh connections, ssh port number, sub, subdomains, time, tip, www
Posted in Linux, System Administration | No Comments »
Wednesday, July 13th, 2011 One server with a broken Raid array was having troubles with it’s software raid.
I tried to scan the raid array via a rescue cd like so:
server:~# mdadm --assemble --scan /dev/md1
just to be suprised by the message:
mdadm: /dev/md1 assembled from 2 drives – not enough to start the array.
In /proc/mdstat respectively the raid was showing inactive, e.g.:
server:~# cat /proc/mdstat
Personalities : [raid10] [raid1]
md1 : inactive sda2[0] sdc2[2] sdb2[1]
12024384 blocks
Respectively trying to activate the software Linux raid array with:
server:~# mdadm -A -s
Couldn’t be completed because of the same annoying error:
/dev/md1 assembled from 2 drives – not enough to start the array.
Thanksfully finally thanks to some Russian, who posted having same issues reported to be able to active his software RAID with mdadm’s –force option.
Thus enabling the problematic RAID 5 array was possible with:
server:~# mdadm -A -s --force
This solution of course is temporary and will have to further check what’s wrong with the array, however at least now I can chroot to the server’s / directory. 😉
Tags: annoying error, cat, check, course, dev, drive, ERROR, force option, Linux, md1, mdstat, option, Personalities, proc, Raid, raid 5 array, raid array, rescue, rescue cd, sCould, sda, sdb, sdc, software, software linux, software raid, solution, Thanksfully, way
Posted in Linux, System Administration | 1 Comment »
Wednesday, July 6th, 2011 
I needed to generate new password for proxy user configured on SQUID proxy server configured with digest user authentication.
My dear colleague was kind to provide me with the below script, which generates the one line string which needs to go to the squid user password file:
#!/bin/sh
user="$1";
realm="$2";
pass="$3";
if [ -z "$1" -o -z "$2" -o -z "$3" ] ; then
echo "Usage: $0 user password 'realm'";
exit 1
fi
ha1=$(echo -n "$user:$realm:$pass"|md5sum |cut -f1 -d' ')
echo "$user:$realm:$ha1"
You can alternatively download the squid_generate_pass.sh script here
The script accepts three arguments;
proxy-server:~# ./squid_generate_pass.sh
Usage: ./squid_generate_pass.sh user password 'realm'
Thus to generate a new user and password and insert it immediately into let’s say a squid configured user/pass file in /etc/squid3/users execute command:
proxy-server:~# ./squid_generate_pass.sh admin_user MySecretPassword 'Squid_Configured_Realm'
>> /etc/squid3/users
Where Squid_Configured_Realm depends on the realm name configured in squid.conf, for example if squid.conf includes some auth configuration similar to:
auth_param digest program /usr/lib/squid3/digest_pw_auth -c /etc/squid3/users
auth_param digest children 2
auth_param digest realm My_Proxy_Realm
acl localusers proxy_auth REQUIRED
The realm script argument should be My_Proxy_realm . If squid_generate_pass does completes without errors, it should add a line to /etc/squid3/users file similar to:
proxy-server:~# cat /etc/squid3/users
admin_user:My_Proxy_realm:3bbcb35e505c52a0024ef2e3ab1910b0
Cheers 😉
Tags: bbcb, cat, Cheers, command, conf, configured, dear colleague, digest authentication, download, exit 1, fi, fiha, file, kind, lib, line, line string, name, param, password, proxy, proxy server, proxy user, pw, realm, realm name, shuser, squid, sum, Usage, user authentication, usersadmin, usersauth, usr
Posted in Linux, System Administration | 1 Comment »
