Snippet : string number increment(done with macro)

#include
#include
#include


#define strincr(s,l) ({int i = l - 1; for(;i>=0 && (s)[i] == '9';(s)[i--] = '0'); (i>= 0) && (++(s)[i]); s;})

char a[4] = "999";

int main(int argv, char **args){

char *s = strincr(a, strlen(a));

strincr(s, strlen(s));

printf("%s", s);
return 0;
}


Just for fun, that might not be faster than by the regular way of using 'atoi'

To Change USB Disk Label in Linux

RenameUSBDrive - Community Ubuntu Documentation

There are 6 programs used to label a partition - the program used depends on the partition's filesystem type:

*

For FAT16 and FAT32 partitions, use mtools.
*

For NTFS partitions, use ntfsprogs.
*

For ext2 or ext3 partitions, use e2label.
*

For JFS partitions, use jfs_tune.
*

For ReiserFS (v3) partitions, use reiserfstune.
*

For XFS partitions, use xfs_admin

performance camparison between php4 and php5

zz from sourceLib

The hardware used was a 2 CPU server, where each CPU was a Intel Xeon 2.8Ghz processor.

The machine contained 2Gig of RAM(DDR2 PC3200 ECC REG 400). The hard drives on the machine were 2-40Gig SATA.

The server was running Red Hat Enterprise Linux version 3.2 with the kernel version 2.4.21-27 and the x86_64 architecture.

The version of Apache running on the machine was 1.3.33.

Each version of PHP was built with the following configuration settings:

With mysql
With ftp enabled
With pcntl (process control) enabled
With memory limit enabled
With cgi disabled

The default php.ini was used as well.

Test	PHP4	PHP5	Net
test_arithmetic	0.065	0.063	3.54%
test_array_operators	0.059	0.058	1.85%
test_bitwise	0.029	0.025	13.19%
test_casting	0.186	0.176	5.63%
test_chr_fixed	0.342	0.336	1.87%
test_chr_hardcoded	0.191	0.181	4.83%
test_chr_var	0.364	0.358	1.68%
test_comment_loop	0.079	0.070	11.50%
test_compare	0.054	0.049	9.98%
test_compare_false	0.008	0.008	0.00%
test_compare_invert	0.005	0.004	8.89%
test_compare_strict	0.014	0.012	18.88%
test_compare_unstrict	0.017	0.014	18.13%
test_constants	0.039	0.039	-2.34%
test_crc32	0.016	0.017	-4.43%
test_do_while	0.390	0.353	9.54%
test_do_while_break	0.056	0.048	14.70%
test_empty	0.004	0.004	13.95%
test_empty_loop	0.078	0.070	10.65%
test_ereg	1.000	1.017	-1.63%
test_foreach	1.240	1.120	9.68%
test_get_class	0.017	0.017	1.15%
test_global_scalar_assign	0.085	0.071	16.17%
test_global_string_assign	0.140	0.129	7.85%
test_if_constant	0.010	0.010	0.00%
test_increment	0.043	0.041	5.07%
test_is_array	0.009	0.008	5.88%
test_is_object	0.008	0.008	2.38%
test_is_type	0.029	0.027	8.16%
test_isset	0.005	0.004	18.37%
test_line	0.009	0.008	2.35%
test_local_array_assign	0.187	0.176	5.73%
test_local_boolean_assign	0.074	0.073	0.41%
test_local_float_assign	0.048	0.044	8.88%
test_local_hash_assign	0.040	0.038	5.28%
test_local_integer_assign	0.048	0.044	7.92%
test_local_object_assign	0.028	0.023	20.49%
test_local_scalar_assign	0.086	0.074	13.08%
test_local_string_assign	0.123	0.114	7.25%
test_md5	0.078	0.077	1.79%
test_microtime	0.075	0.087	-15.65%
test_mt_rand	0.011	0.011	0.00%
test_ord	1.447	1.416	2.17%
test_ordered_functions	0.629	0.602	4.18%
test_ordered_functions_references	0.603	0.576	4.56%
test_preg_match	0.050	0.065	-29.37%
test_rand	0.011	0.011	-0.94%
test_references	0.017	0.015	12.21%
test_sha1	0.094	0.099	-5.98%
test_string_append	0.091	0.083	8.88%
test_strlen	0.009	0.009	-2.22%
test_switch	0.190	0.191	-0.37%
test_time	0.023	0.023	-1.31%
test_unordered_functions	0.715	0.663	7.35%
test_variable_variables	0.038	0.034	10.90%
test_while	0.423	0.358	15.49%

LAMP starts

First it is ftp. That is always the way one deploy a site to server.

Download vsftp, ./configure and then make install.
Or install with yum or atp.
Edit /etc/vsftpd.conf(or maybe /etc/vsftpd/vsftpd.conf).
To enable anonymous access, add the 2 following line:

anon_root=/data
anon_upload_enable=YES

To add another user,

todo here...

Then we go with mysql 5.0(5.0.51a.)

Get mysql noninstall version, unpack it into /usr/local.
make a symbol link as /usr/local/mysql to /usr/local/mysql.real.path.
and execute the following command to create users and start mysql daemon:

shell> groupadd mysql
shell> useradd -g mysql mysql
shell> cd /usr/local
shell> gunzip < /PATH/TO/MYSQL-VERSION-OS.tar.gz | tar xvf - shell> ln -s FULL-PATH-TO-MYSQL-VERSION-OS mysql
shell> cd mysql
shell> chown -R mysql .
shell> chgrp -R mysql .
shell> scripts/mysql_install_db --user=mysql
shell> chown -R root .
shell> chown -R mysql data
shell> bin/mysqld_safe --user=mysql &

copy one of the support-files/my-*.cnf to /etc/my.cnf as the default mysql config.

To stop mysql : mysqladmin shutdown

If needed, use mysqladmin -u root -p shutdown

After mysql started, we need to add some account to it.

mysql> GRANT ALL PRIVILEGES ON *.* TO 'monty'@'localhost'
-> IDENTIFIED BY 'some_pass' WITH GRANT OPTION;

mysql> GRANT ALL PRIVILEGES ON *.* TO 'monty'@'%'
-> IDENTIFIED BY 'some_pass' WITH GRANT OPTION;

mysql> GRANT RELOAD,PROCESS ON *.* TO 'admin'@'localhost';

mysql> GRANT USAGE ON *.* TO 'dummy'@'localhost';

'all privileges' means this user can do anything.
*.* means all tables
'monty' is the user name, 'localhost' is the ip address from where this user can login.
'some_pass' is password.
'grant option' means this user can do grant operation.

To use old passward format for old mysql client :

mysql> SET PASSWORD FOR
 -> 'some_user'@'some_host' = OLD_PASSWORD('newpwd'); 

Alternative ：

mysql> UPDATE mysql.user SET Password = OLD_PASSWORD('newpwd')
 -> WHERE Host = 'some_host' AND User = 'some_user';

mysql> FLUSH PRIVILEGES; 

Or：

Start mysqld with the --old-passwords option.

Then we go with php5 (mysql 4.1 or later requires php 5).

download php source &

./configure --with-mysql & make install.

Where's it in iphone

in iphone 1.1.3:
addressbook : /var/mobile/Library/AddressBook

core dump

gdb exec_name core.pid

dynamic lib in linux

/etc/ld.so.conf
dynamic libs config file

command : ldconfig
Each time after changing that file, run 'ldconfig' to flush config data.

command : ldd
Check which lib has been linked by an executable.
example : ldd a.out

libpthread.so.0 => /lib/tls/libpthread.so.0 (0x00986000)
libc.so.6 => /lib/tls/libc.so.6 (0x0081c000)
/lib/ld-linux.so.2 (0x007fe000)

command : objdump
Print out many useful information about an executable file.
example : objdump -p a.out

a.out：     文件格式 elf32-i386

程序头：
    PHDR off    0x00000034 vaddr 0x08048034 paddr 0x08048034 align 2**2
         filesz 0x000000e0 memsz 0x000000e0 flags r-x
  INTERP off    0x00000114 vaddr 0x08048114 paddr 0x08048114 align 2**0
         filesz 0x00000013 memsz 0x00000013 flags r--
    LOAD off    0x00000000 vaddr 0x08048000 paddr 0x08048000 align 2**12
    ....
动态节：
  NEEDED      libpthread.so.0
  NEEDED      libc.so.6
    ....

版本引用：
  required from libpthread.so.0:
    0x0d696910 0x00 04 GLIBC_2.0
    0x0d696911 0x00 03 GLIBC_2.1
  required from libc.so.6:
    0x0d696910 0x00 02 GLIBC_2.0