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Packing, unpacking, and installing files:
gzip compress:
#gzip <filename.ext>
gzip extract:
#gunzip <filename.ext>
gzip retrieve information about file:
#gzip -l <filename.ext>
tar archive:
#tar cfv <archive name.ext> <file/folder to archive>
tar extract:
#tar xvf <filename.ext>
tar retrieve information about file:
#tar tvf <filename.tar>
gzip and tar compress in one command:
#tar cvzf <archive name.tar.gz> <file/folder to
archive>
gzip and tar extract in one command:
#tar xvzf <filename.tar.gz>
install rpm files:
#rpm -ivh <rpm file name>
install rpm package even if already installed:
#rpm -ivh --replacepkgs <rpm file name>
uninstall rpm packages:
#rpm -e <rpm package name>
After uninstalling an rpm package, you will find that it still has config files and other bits strewn about. The rm -rf and rm -f commands are VERY powerful and can easily render your linux installation unusable. Be very careful. A 'reasonably safe' way (provided you pay attention and are careful) to clean the files up is:
1) Do a find / -name "<filename>*" | more
2) Check the output and make SURE it only includes the files you want to remove.
3) Do a find / -name "<filename>*" | xargs rm -f
tar basic functions and options:
function:
c To create a new archive
x To extract files from an archive
t To list the contents of an archive
r To append files to the end of an archive
u To update files that are newer than those in the archive
d To compare files in the archive to those in the filesystem
options:
f <filename> To specify that the tar file to be read or
written is named <filename>
k To keep any existing files when extracting, i.e. don't delete
the origional files
v To make tar show the files it is archiving or restoring (don't
use in shell scripts)
z To specify that the data to be written to the tar file should
be gzipped
Miscellaneous commands:
To download a web page(s):
#wget -m -r -l5
Checking open network ports:
#netstat -apn | more
Show file attributes and permissions:
#ll
Show all files in a directory (including hidden .<name>
files
#ls -A
Show information about mounted volumes:
#df -h
Turn off all power management:
#xset -dpms
Load StartX setup routine:
#X86config
Display log file starting at the end:
#tail -f <file name>
Samba commands:
Add user/change password (user must have a unix account first):
#smbpasswd -a <username>
Apache commands:
.htpasswd file creation for Apache Directory security use:
To create a new .htpasswd file and add a user (will prompt for
password):
#htpasswd -c /etc/httpd/conf/.htpasswd <name>
To create a new user in an existing .htpasswd file (will prompt
for password):
#htpasswd /etc/httpd/conf/.htpasswd <name>
<Directory> security examples in httpd.conf (which use
the .htpasswd file):
<Directory "/var/www/html/<directory>">
AuthType Basic
AuthName "Restricted Uploads"
AuthUserFile /etc/httpd/conf/.htpasswd
Require valid-user (means anyone in the .htpasswd file can
access)
</Directory>
**and**
<Directory "/var/www/html/<directory>">
AuthType Basic
AuthName "Restricted file access"
AuthUserFile /etc/httpd/conf/.htpasswd
Require jjones (only jjones in the .htpasswd file has access)
</Directory>
RedHat/Fedora account creation:
To create a new user account:
#useradd <name>
To add/change a password:
#passwd <name> (will prompt for password twice)
To add a user to a group:
#usermod -G <groupname> <username>
Set owner of a file/folder:
#chown <user.group> <file/folder name>
#chown -R >user.group> <file/folder
name> for recursive, i.e. apply changes to subfolders
Set permissions on a file/folder:
#chmod 777 <file/folder name> for full rights (dangerous!)
#chmod 775 <file/folder name> for full rights for
user/group but no write/execute for 'other'
#chmod 765 <file/folder name> for full user rights,
no write for 'group', and no write/execute for 'other'
Add -R for recursive, i.e. chmod -R 775
<file/folder name> to apply rights to subfolders
File permissions take the form of:
| User |
Group |
Other |
| -RWX |
RWX |
RWX |
The leading dash in the above table is for the type of data,
d would be a directory and - indicates a file.
File permissions can be set using bits, as referenced above:
| User |
Group |
Other |
| read |
write |
execute |
read |
write |
execute |
read |
write |
execute |
| 400 |
200 |
100 |
40 |
20 |
10 |
4 |
2 |
1 |
Another way to look at it would be to visualize -r--r--r-- and
calculate it as:
~examples~
File permissions of -rwxrwxr-x would be:
400+200+100 plus 40+20+10 plus 4+1 (no write for Other) which
equals 775
File permissions of -rwxr-xr-x would be:
400+200+100 plus 40+10 plus 4+1 (no write for Group or Other)
which equals 755
So, chmod -R 775 /var/www/html means /html and subfolders
have -rwxrwxr-x or full rights except 'Other', which doesn't
have write permissions.
Making symbolic links:
#ln -s <location/filename> <name of symbolic
link>
Example: ln -s /var/www/html/homesite homesite would create
a link named homesite to /var/www/html/homesite which is a folder.
Sending Root system messages and logs to an email address:
Edit /etc/aliases
Un-remark (remove # symbol) from 'root:' and add the email address
of the recipient.
Save file.
At the command prompt, type newaliases to update the database.
Enable daily yum updates:
Pre-FC6 setup:
# chkconfig yum on
# service yum start
Should see "Enabling nightly yum update: [OK]"
FC6 and later setup (yum-cron is a seperate package):
# yum install yum-cron
# chkconfig yum-cron on
# service yum-cron start
Should see "Enabling nightly yum update: [OK]"
Other yum features:
List all available software:
#yum list
See if there are updated packages available:
#yum check-update
Update all installed packages that have a newer version available:
#yum update
Install specific package(s) (and its dependencies, if missing any):
#yum install <packagename>
Search all known packages entries (descriptions etc) for <word>
#yum search <word>
Show basic information about a package
#yum info <packagename>
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