Ivorde Unix/Linux/Database/Web/Mail Forum

**Posted:** Tue Nov 01, 2011 4:50 pm

Giving that a system has ntpd up&running, ntpq utility can be used to check system time synchronization:

Code:

# ntpq -pn
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
+80.96.120.251   .PPS.            1 u  984 1024  377   10.723   -0.909   1.437
+80.96.120.252   .PPS.            1 u  851 1024  377   10.800   -0.503   0.476
*80.96.120.253   .PPS.            1 u 1019 1024  377   10.611   -0.698   0.669

Man ntpq quote:

Quote:

NTPQ(8) FreeBSD System Manager's Manual NTPQ(8)

NAME
ntpq -- ...

**Posted:** Mon Oct 31, 2011 2:03 pm

In Bash shell, redirecting output to a existing file is not possible if the "noclobber" bash option is set.

To overcome this, use the ">|" or ">>" redirect operator. The pipe will overwrite the file if you are using single angle bracket and append if you're using double angle brackets.

How to forcely overwrite a file with output from a command:

# cat output
# echo 'output' >output
-bash: output: cannot overwrite existing file ...

**Posted:** Mon Oct 31, 2011 1:54 pm

A little background from bashref:http://www.gnu.org/software/bash/manual/bashref.html

Quote:

3.2.4.3 Grouping Commands

Bash provides two ways to group a list of commands to be executed as a unit. When commands are grouped, redirections may be applied to the entire command list. For example, the output of all the commands in the list may be redirected to a single stream.

()
( list )

Placing a list of commands between parentheses causes a subshell environment to be created (see Command ...

**Posted:** Thu Apr 07, 2011 1:50 pm

When having multiple man files from multiple daemons with the same name (ie: /usr/share/man/man8/tftpd.8.gz from freebsd stock tftpd daemon and /usr/local/man/man8/tftpd.8.gz from yale-tftpd packet), the man tftpd command will show the content of the default tftpd.8.gz man page (/usr/share/man/man8/tftpd.8.gz).

Code:

# pkg_info -L freebsd*; pkg_info -L yale*
Information for freebsd-tftp-1.0:

Files:
/usr/bin/tftp
/usr/libexec/tftpd
/usr/share/man/man1/tftp.1.gz
/usr/share/man/man8/tftpd.8.gz

Information for yale-tftpd-3.0:

Files:
/usr/local/libexec/tftpd
/usr/local/man/man8/tftpd.8.gz

If you want to see the man page from yale-tftpd (/usr/local/man/man8/tftpd.8.gz), you can change ...

**Posted:** Thu Mar 03, 2011 12:58 pm

Ever had the putty/securecrt/terminal looking like this after cat-ing a binary or echoing encrypted content ?

Code:

[⎼⎺⎺├@├␤⎺⎼ ·]# 
[⎼⎺⎺├@├␤⎺⎼ ·]# 
[⎼⎺⎺├@├␤⎺⎼ ·]# 
[⎼⎺⎺├@├␤⎺⎼ ·]# ␊␌␤⎺ '\17'
\17
[⎼⎺⎺├@├␤⎺⎼ ·]# ␊␌␤⎺ -␊ '\␊(0'

There are many solutions on the web, but not all work all the time. Here's one that worked everytime for me:

Code:

echo -e '\017'

**Posted:** Fri Oct 08, 2010 5:22 pm

This is most probably because of the /var/log/wtmp file which, if it goes over ~4.5GB, getty processes will not be able to create virtual terminals and all sorts of login problems from here on (sshd, telnet and so on).

**Posted:** Wed Aug 04, 2010 10:44 am

Some binaries or some command output (unexpected) can contain control sequence which can cause a terminal to interpret it as changing character set. That's why the prompt becomes unreadable and keystrokes abnormal (lines).

To fix this, there are few possible solutions:

Code:

$ echo -e '\017'

or

Code:

$ reset

(NOT REBOOT)
or

Code:

$ stty sane

**Posted:** Thu Jul 29, 2010 6:34 pm

After installing Apache 2.2.3 on Centos 5.5, adding virtual domains with Directory indexes will not be possible and the apache welcome page will be displayed if there isn't an index file in the root directory of the vhost.

Quote:

Directory index forbidden by Options directive

This behavior can be fixed by editing /etc/httpd/conf.d/welcome.conf and change it from:

Code:

<LocationMatch "^/+$">
    Options -Indexes
    ErrorDocument 403 /error/noindex.html
</LocationMatch>

to

Code:

<LocationMatch "^/+$">
    Options Indexes
    ErrorDocument 403 /error/noindex.html
</LocationMatch>

...

**Posted:** Thu Jul 29, 2010 10:00 am

While running the cyrus2courier perl script, I ran into the following error:

Quote:

# /usr/bin/perl /tmp/maildir2cyrus-uid-internaldate
Can't locate Mail/Header.pm in @INC (@INC contains: /usr/local/lib/perl5/5.8.8/BSDPAN /usr/local/lib/perl5/site_perl/5.8.8/mach /usr/local/lib/perl5/site_perl/5.8.8 /usr/local/lib/perl5/site_perl /usr/local/lib/perl5/5.8.8/mach /usr/local/lib/perl5/5.8.8 .) at /tmp/maildir2cyrus-uid-internaldate line 60.
BEGIN failed--compilation aborted at /tmp/maildir2cyrus-uid-internaldate line 60.

For this, the perl MailTools module is needed.

To install Mail-Tools perl module on FreeBSD:
# make install -C /usr/ports/mail/p5-Mail-Tools
===> License check disabled, port has not defined LICENSE
=> MailTools-2.06.tar.gz doesn't seem to ...

**Posted:** Thu Jul 22, 2010 9:30 pm

Quote:

Syntax error on line 428 of /opt/apache-2.2.15_9/etc/apache22/httpd.conf:
Invalid command 'AddHandler', perhaps misspelled or defined by a module not included in the server configuration

I started compiling apache from scratch (I removed almost all the modules). The error above was expected when installing php module.

Fix is to use apche APXS utility to install modules without recompiling apache:

Code:

# /opt/apache-2.2.15_9/sbin/apxs -c -i mod_mime.c

Caution: Use apxs from the version of Apache you want the module ...

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