yum 安裝發生"Header is not complete"

使用YUM install 或Yum update 每一個下載的RPM都發生同樣的Error  "Header is not complete"，從系統或網路上始終找不出問題，後來想到可能是對外Firewall在搞鬼，拿掉Fortigate的Protection Profile後就可以正常使用Yum...

/tmp 中的檔案不見

Review 新公司的備份機制，發現備份的samba server中的檔案都會不見，而且是剛備份完是完整的，隔天檔案就不見了大半，後來檢查crontab job,發現dailly中有一個可疑的script "tmpwatch"，原來這個script會定期刪掉720小時未存取的tmp檔案，前任網管又把備份的目錄設在/tmp，難怪會不見檔案，經一事長一智…..感謝前人的錯誤。

mysql 的ROOT密碼忘記

先將mysql停止
#service mysqld stop
將mysqld啟動並設為無登入控制模式
#mysqld_safe --skip-grant-tables&
登入mysql,注意喔,我沒輸入帳號密碼
#mysql
重新將mysql上的root密碼設定為1234
mysql> update mysql.user set password=PASSWORD('1234') where user='root';
讓剛剛的命令生效(修改或刪除帳號必須手動生效)
mysql> flush privileges;
離開mysql指令列
mysql> quit
重新啟動mysqld
#service mysqld restart

rpm 安裝時發生 Segmentation fault

rpm 安裝時發生　Segmentation fault

可能是RPM的ｄｂ出了問題，

試試

rpm --rebuilddb　重修復ｄｂ

或

rpm --initdb    重建立ｄｂ

　　

尋找Linux某一檔案內容的字串

find /home/user  -type f  -exec grep -l test {} \; 

-type f 只搜尋檔案（不然會find一堆目錄來比對） 

 

 

使用NTOP管理網路流量

管理頻寬使用量的常用工具
Openview
MRTG
sniffer,ethereal
Webtrend for Firewall
BandwidthD,Ntop
（以上我都有用，最常使用的是mrtg及ntop）

NTOP 的簡介
NTOP的發展原是為因對網路頻寬使用狀況的掌握，正如運用unix系統中的top指令以瞭解系統資源使用狀況一樣，可用圖形化的介面了解頻寬的使用情形.

NTOP 的運作原理
利用libpcap 的擷取封包功能將封包分析後存入資料庫，並將其結果輸出

NTOP的限制
只能用於區域網路內
無法跨SWITCH
硬體需求高，需要記憶體儲存擷取封包的資訊。

最近把google map及whois的功能新增進去，可反查ip的位置及owner。

php頁面都是空白的

修改php.ini

short_open_tag = off

改成 ON

 

/etc/rc.d/init.d/xxxxx 的編輯說明,& check process 是否已經在running

#!/bin/bash
#
# /etc/rc.d/init.d/<servicename>
#
# <description of the *service*>
# <any general comments about this init script>

#
# <tags -- see below for tag definitions. *Every line* from the top
# of the file to the end of the tags section must begin with a #
# character. After the tags section, there should be a blank line.
# This keeps normal comments in the rest of the file from being
# mistaken for tags, should they happen to fit the pattern.>

# Source function library.
. /etc/rc.d/init.d/functions

case "$1" in
start)
echo -n "Starting <servicename> services: "
<start daemons, perhaps with the daemon function>
touch /var/lock/subsys/<servicename>
;;
stop)
echo -n "Shutting down <servicename> services: "
<stop daemons, perhaps with the killproc function>
rm -f /var/lock/subsys/<servicename>
;;
status)
<report the status of the daemons in free-form format,
perhaps with the status function>
;;
restart)
<restart the daemons, normally with $0 stop; $0 start>
;;
reload)
<cause the service configuration to be reread, either with
kill -HUP or by restarting the daemons, possibly with
$0 stop; $0 start>
;;
probe)
<optional. If it exists, then it should determine whether
or not the service needs to be restarted or reloaded (or
whatever) in order to activate any changes in the configuration
scripts. It should print out a list of commands to give to
$0; see the description under the probe tag below.>
;;
*)
echo "Usage: <servicename> {start|stop|status|reload|restart[|probe]"
exit 1
;;
esac

Functions in /etc/rc.d/init.d/functions

daemon [+/-nicelevel] program [arguments] [&]

Starts a daemon, if it is not already running.

Does other useful things like keeping the daemon from dumping core if it terminates unexpectedly.

killproc program [signal]

Sends a signal to the program; by default it sends a SIGTERM,

and if the process doesn't die, it sends a SIGKILL a few seconds later.

It also tries to remove the pidfile, if it finds one.

pidofproc program

Tries to find the pid of a program; checking likely pidfiles,

using the pidof program, or even using ps. Used mainly from within other functions in this file, but also available to scripts.

status program

Prints status information. Assumes that the program name is the same as the servicename.

Tags.

# chkconfig: <startlevellist> <startpriority> <endpriority>

Required. <startlevellist> is a list of levels in which the service should be started by default.

<startpriority> and <endpriority> are priority numbers.

For example: # chkconfig: 2345 20 80 Read 'man chkconfig' for more information.

Unless there is a VERY GOOD, EXPLICIT reason to the contrary,

the <endpriority> should be equal to 100 - <startpriority>

# description: <multi-line description of service>

Required. Several lines of description, continued with '\' characters.

The initial comment and following whitespace on the following lines is ignored.

# description[ln]: <multi-line description of service in the language \ # ln, whatever that is>

Optional. Should be the description translated into the specified language.

# processname:

Optional, multiple entries allowed. For each process name started by the script,

there should be a processname entry. For example, the samba service starts two daemons:
# processname: smdb
# processname: nmdb

# config:

Optional, multiple entries allowed. For each static config file used by the daemon, use a single entry. For example:
# config: /etc/httpd/conf/httpd.conf
# config: /etc/httpd/conf/srm.conf

Optionally, if the server will automatically reload the config file if it is changed,

you can append the word "autoreload" to the line:
# config: /etc/foobar.conf autoreload

# pidfile:

Optional, multiple entries allowed.

Use just like the config entry, except that it points at pidfiles.

It is assumed that the pidfiles are only updated at process creation time, and not later.

The first line of this file should be the ASCII representation of the PID;

a terminating newline is optional. Any lines other than the first line are not examined.

# probe: true

# Check for postmaster already running...
pid=`pidof postmaster`
if [ $pid ]
then
echo "Postmaster already running."
else
run xxx <<<<< else 要run 的指令
fi <<<<等於endif的意思

為網路卡設置固定的速度

1) 檢查網路交換器 (或路由器)，並將其設定為網路卡欲使用的速度 (它有可能被設成 100)。
2) 修改檔案: /etc/sysconfig/network-scripts/ifcfg-ethX
並且加入下面這行:
ETHTOOL_OPTS="speed 1000 duplex full"
3) 重新啟動網路卡程序，或者重新開機。

如何建立可開機的 USB 隨身碟?

如何建立可開機的 USB 隨身碟?

組態資訊
Redhat Enterprise Linux 2.1 版及 3.0 版
解決方法
請依照下列步驟建立可開機的 USB 隨身碟:
1. 以 /dev/loop 掛載 (Mount) ISO 映像檔:
  # mkdir /mnt/tmpmount
  # mount -o,loop=/dev/loop1 boot.iso /mnt/tmpmount
2. 將檔案從掛載點 (Mount Point) 複製到一個暫存的子目錄:
  # mkdir /tmp/usbimage
  # cp -Rv /mnt/tmpmount/isolinux/* /tmp/usbimage/
3. 將 isolinux.img 和 isolinux.cfg 重新命名為 syslinux.img 和 syslinux.cfg:
4. 建立一個足夠容納這些檔案的空白檔案:
  # dd if=/dev/zero of=/root/usbboot.img bs=1M count=7
以上命令會建立一個 7MB 的檔案，這應該夠大了。
5. 在 usbboot.img 上建立一個檔案系統:
  # mkfs.vfat usbboot.img
6. 卸載 (Unmount) boot.iso 並掛載 usbboot.img:
  # ummount /mnt/tmpmount
  # mount -o,loop=/dev/loop1 /root/usbmount.img /mnt/tmpmount
7. 將檔案複製到已掛載的檔案系統:
  # cp -Rv /tmp/usbimage/isolinux/* /mnt/tmpmount
8. 卸載 /mnt/tmpmount:
  # umount /mnt/tmpmount
9. 將 sbmount.img 設成 "可開機":
  # syslinux /root/usbboot.img
10. 插入 USB 隨身碟，然後將開機映像檔置入:
  # dd if=/root/usbboot.img of=/dev/sda bs=1M
完成之後，您便擁有一個可開機的 USB 隨身碟。此隨身碟可在 DL 140、145、3xx G4 等
系統上使用。請進入 BIOS 設定，將 USB 設成開機裝置。

新增phpmyadmin權限控制;新增mysql user

1.修改phpMyAdmin的設定檔config.inc.php

      -設定 phpMyAdmin 認證模式:$cfg['Servers'][$i]['auth_type'] = 'http';
      -改為http表示透過瀏覽器輸入帳號及密碼進行MySQL的認證,並把$cfg['Servers'][$i]['user']  &['password']='';  <===原設定拿掉
      -若用config，則需要將密碼寫入檔案,設定如下
           $cfg['Servers'][$i]['user'] = 'rdcenter';
           $cfg['Servers'][$i]['password'] = 'rdxxxx';
2.新增mysql user,並給予權限

      mysql> grant all privileges on net00db.* to net00@localhost IDENTIFIED BY '12345678' ;

      mysql> grant select on TotalClickBoard.* to cti@localhost IDENTIFIED BY '16318448' ;

      mysql> FLUSH PRIVILEGES ; 

php頁面都是空白的

修改php.ini

short_open_tag = off

改成 ON

尋找N天前的檔案,並做刪除

find . -mtime 8 -exec rm -f {} \; 刪除8天前(那一天)的檔案

find . -mtime 5 -exec ls -la {} \; list出5天前(那一天)的檔案

find . \! -cnewer dfk661Gn08001163 -exec rm -f {} \; 刪除比dfk661Gn08001163還舊的檔案( \! -cnewer=-cnewer的相反)

Linux 檢查檔案數目

ls -la |more

ls -la | wc -l

用在檢查大量的mail queue時很有用.

如何測試ide硬碟性能及增加IDE硬碟效能

使用hdparm -tT /dev/hdX就可以测试硬碟的buffer-cache reads和buffered disk reads两个数据，可以用来当作硬盘性能的参考。

同时使用hdparm -c3 /dev/hdaX还能设置硬盘以32bit传输，以加快数据传输的速度。



hdparm -c3 -d1 -m16 -X66 /dev/hda 目前使用ide硬碟的機器都要設定以增加速度

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