Linux: Install a Package on Redhat Linux

1.check what packages had been installed on the server:
#rpm -q binutils compat-db control-center gcc gcc-c++ glibc glibc-common \
gnome-libs libstdc++ libstdc++-devel make pdksh sysstat xscreensaver \
libaio openmotif21

binutils-2.15.92.0.2-13
compat-db-4.1.25-9
control-center-2.8.0-12
gcc-3.4.3-22.1
gcc-c++-3.4.3-22.1
glibc-2.3.4-2.9
glibc-common-2.3.4-2.9
gnome-libs-1.4.1.2.90-44.1
libstdc++-3.4.3-22.1
libstdc++-devel-3.4.3-22.1
make-3.80-5
pdksh-5.2.14-30
package sysstat is not installed
xscreensaver-4.18-5.rhel4.2
libaio-0.3.103-3
openmotif21-2.1.30-11.RHEL4.4

the above commend will display packages had been installed for:

binutils compat-db control-center gcc gcc-c++ glibc glibc-common gnome-libs libstdc++ libstdc++-devel make pdksh sysstat xscreensaver libaio openmotif21

the “\ “is a line braker. This command will print the package name, version, and release number of installed package foo. Use this command to verify that a package is or is not installed on your system.

2.Install a package
#rpm -ivh foo-1.0-2.i386.rpm

It is also better to use Update , rpm –Uvh (see 4), to install packages, since it works fine even when there are no previous versions of the package installed. This way, it will not give error if a package already exists.

3.Uninstall a package
#rpm –e foo

Notice that we used the package name foo, not the name of the original package file foo-1.0-2.i386.rpm.

4.Update a RPM package.
#rpm -Uvh foo-1.0-2.i386.rpm
With this command, RPM automatically uninstall the old version of foo package and install the new one. Always use rpm -Uvh to install packages, since it works fine even when there are no previous versions of the package installed.

5.Display package Information
# rpm -qi foo
This command display package information; includes name, version, and description of the installed program. Use this command to get information about the installed package.
6.List Files in package
# rpm –qlfoo
This command will list all files in a installed RPM package. It works only when the package is already installed on your system.
7.Check RPM Signature package
#rpm –checksig foo
This command checks the PGP signature of specified package to ensure its integrity and origin. Always use this command first before installing new RPM package on your system. Also, GnuPG or Pgp software must be already installed on your system before you can use this command.

MySql: Change Root Password

1. Use Mysqladmin Command To Change Root  User Password

If you have never set a root password for MySQL, the server does not require a password at all for connecting as root. To setup root password for first time, use mysqladmin command at shell prompt as follows:

$ mysqladmin -u root password NEWPASSWORD

However, if you want to change (or update) a root password, then you need to use following command

$ mysqladmin -u root -p oldpassword newpass

Enter password:

2.  Reset /Recover MySQL Root Password

In case you can not remember the root password, following steps can be used to reset the password.
Here are commands you need to type for each step (login as the root user):

 Step # 1 : Stop mysql service

# /etc/init.d/mysql stop

Output:

Stopping MySQL database server: mysqld.

Step # 2: Start to MySQL server w/o password:

# mysqld_safe --skip-grant-tables;

Output:

[1] 5988

Starting mysqld daemon with databases from /var/lib/mysql

mysqld_safe[6025]: started

Step # 3: Connect to mysql server using mysql client:

# mysql -u root

Output:

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 1 to server version: 5.0.1

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql>

Step # 4: Setup new MySQL root user password

mysql> use mysql;

mysql> update user set password=PASSWORD("NEW-ROOT-PASSWORD") where User='root';

mysql>flush privileges;

mysql>quit

Step # 5: Stop MySQL Server:

# /etc/init.d/mysql stop

Output:

Stopping MySQL database server: mysqld

STOPPING server from pid file /var/run/mysqld/mysqld.pid

 Step # 6: Start MySQL server and test it

# /etc/init.d/mysql start

# mysql -u root -p

Enter password.

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