Here some of the most useful debian commands are listed:
List all open ports and applications that hold them.
lsof -i
useful is also:
netstat -tunap
Search the package database for the package xyz.
apt-cache search xyz
Get package information for the package xyz.
apt-cache show xyz
Install the package xyz
apg-get install xyz
Look for a file pcre.h in all packages using the regular expression
apt-file search -x "/pcre.h$"
Set the access rights of all files in the current directory and all files in subdirs to 644 (check unix access rights for help on this topic).
find . -type f -print0 | xargs -0 chmod 644
Set access rights for all directories in current dir and for all subdirs to 755.
find . -type d -print0 | xargs -0 chmod 755
Find help on the command chmod:
man chmod
Check all .sfv files found in a directory (and its subdirs):
find . -type f -name *.sfv -execdir cfv -f {} \;
cfv must be installed!
apt-get install cfv
Extract all files/folders in archive.tar to the current directory and create directory structure.
tar xvf archive.tar.gz
Add all files/folders to archive from the specified directory
tar -pczf archive.tar.gz folder/
Check the space available on the hard drives.
df -h
Show the size of a directory.
du ./folder/ --max-depth=0 -h
Find all files in a directory containing a specific string.
find /Search/Path -type f | xargs strings -f | fgrep -i SearchString
Pass a command as parameter to a program:
./program `command`
For example pass file content to a program as first parameter:
./program `< file.txt`
Installs a init.d script using the given comments in the file into the bootup sequence
insserv -d scriptname
Removes a init.d script from bootup sequence
insserv -r scriptname
After configuring a package and running make, instead of make install you can
execute the checkinstall command. It will build a package and install it on the system.
This package can then be removed easily with dpkg.
Login as www-data user:
You have to provide a shell, since by default none is set for
this user...
So use: su -s /bin/bash www-data
If running apt-get update returns an error because of changed sources.list (new version f.e.),
just update the debian keyring like that:
apt-get install debian-keyring debian-archive-keyring
The next execution of update should work without any problems.