Tools for Linux, MySQL, OpenVZ...

Useful tools for Linux, MySQL, OpenVZ, etc.

dstat - disk and memory statistics
vmstat - virtual hosts statistics
htop - like top but more user friendly
mytop - like top but does MySQL monitoring
ipcs - ipc facilities info
ntop - like top but for network statistics
gparted - GNOME partition editor, allows drag and drop (partition magic for Linux)

Subversion keywords: svn propset

While commiting file into subversion you can get following error:

File: trunk/etc/init.d/apache-local
Appears to be a text file, yet it does not allow RCS Id substitution.
Sorry, this is a rule. Please fix svn:keywords.


Solution

svn propset 'svn:keywords' 'Author Date Id Revision' file-name


Shell alias

alias svnpropset='svn propset '\''svn:keywords'\'' '\''Author Date Id Revision'\'''


Other examples

set file executable flag:
svn propset 'svn:executable' 1 filename


Another svn task: list files which will be altered by further svn update
svn st -u

SSH file system: FUSE

Install:
apt-get install sshfs

Mount remote home:
sshfs hostname: mountpoint

Mount under different user:
sshfs user@hostname: mountpoint

Mount specific path:
sshfs hostname:/path mountpoint

Umount:
fusermount -u mountpoint

source: http://fuse.sourceforge.net/sshfs.html

Burning DVD in Debian Linux

Burning CD / DVD under Debian / Kubuntu

# Install k3b
apt-get install k3b libk3b2-extracodecs

# Suggested packages
k3b-i18n movixmaker-2 normalize-audio sox toolame

# Run k3b
k3b

Debugging with gdb

If I want to debug some program I miss some handfull guide. Here is one:

Commands 

gdb name-of-executable 

gdb -e name-of-executable -c name-of-core-file 

gdb name-of-executable -pid process-id 

(Use ps -auxw to list process id's.) 

Resources 

Gdb tutorial at yolinux 

Example gdb session and commands 

Software 

cgdb - curses based gdb ide 

ddd - gdb ide for x window

Other Linux Debugging techniques

Linux Applications Debugging Techniques

https://en.wikibooks.org/wiki/Linux_Applications_Debugging_Techniques

Linux Applications Debugging Techniques/The debugger

https://en.wikibooks.org/wiki/Linux_Applications_Debugging_Techniques/The_debugger

Linux Applications Debugging Techniques/Heap corruption

https://en.wikibooks.org/wiki/Linux_Applications_Debugging_Techniques/Heap_corruption

Linux Applications Debugging Techniques/Stack corruption

https://en.wikibooks.org/wiki/Linux_Applications_Debugging_Techniques/Stack_corruption

Linux Applications Debugging Techniques/Leaks

https://en.wikibooks.org/wiki/Linux_Applications_Debugging_Techniques/Leaks

Valgrind usage

valgrind --leak-check=full \

         --show-leak-kinds=all \

         --track-origins=yes \

         --verbose \

         --log-file=valgrind-out.txt \

         ./executable exampleParam1

Q: https://stackoverflow.com/questions/5134891/how-do-i-use-valgrind-to-find-memory-leaks

A: https://stackoverflow.com/a/44989219

GCC compile/link options:

-fsanitize=address

XORs with:

-fsanitize=thread

Q: https://stackoverflow.com/questions/19989323/what-to-use-instead-of-mudflap-with-gcc-llvm-for-detecting-memory-access-bugs

A: https://stackoverflow.com/a/19989324

Oracle OFFSET LIMIT

Q: https://stackoverflow.com/questions/14557751/how-to-get-row-number-from-selected-rows-in-oracle

A: https://stackoverflow.com/a/14557829

ROWNUM psuedocolumn or the ROW_NUMBER()

Q: rowcount https://stackoverflow.com/questions/13653194/rowcount-in-oracle

A:

Q: offset limit https://stackoverflow.com/questions/2912144/alternatives-to-limit-and-offset-for-paging-in-oracle

A: subselect: https://stackoverflow.com/q/2912144

A2: Oracle 12g: https://stackoverflow.com/a/25600033

A3: Oracle 10g: https://stackoverflow.com/a/5221509

 

Must be connected to a terminal

Problem:

Connection to a remote host by ssh and starting screen in one command can cause following error:

ssh user@example.com screen -R -d
Must be connected to a terminal.

Solution:

Provide screen with a terminal by switch -t:

ssh -t user@example.com screen -R -d

Source: wlug.org.nz

MySQL tools and settings

MySQL tools
apt-get install mytop

ANALYZE TABLE;

SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED ;
SET sql_mode='TRADITIONAL' ;

SET AUTOCOMMIT = 0;
SET NAMES utf-8;
SET CHARACTER SET utf-8;

(or optionally: latin2 or cp1250, cp1251, etc.)

source: MySQL modes
source2: MySQL charset