cheat/.cheat

#!/usr/bin/env python

cheatsheets = {

# @todo:
# - adb
# - at
# - dd
# - df
# - du
# - fdisk
# - fstab
# - mount
# - mongodump
# - mongoimport
# - nc
# - rsync
# - useradd / adduser
# - xargs

########## apt-cache ##########################################################
'apt-cache' : '''
To search for apt packages:
apt-cache search "whatever"
''',

########## bash ###############################################################
'bash' : '''
To implement a for loop:
for file in `ls .`;
    do echo 'file';
    echo 'found';
done

@todo: if (esp. file/directory)
''',

########## convert ###########################################################
'convert' : '''
To resize an image to a fixed width and proportional height:
convert original-image.jpg -resize 100x converted-image.jpg

To resize an image to a fixed height and proportional width:
convert original-image.jpg -resize x100 converted-image.jpg

To resize an image to a fixed width and height:
convert original-image.jpg -resize 100x100 converted-image.jpg

To resize an image and simultaneously change its file type:
convert original-image.jpg -resize 100x converted-image.png

To resize all of the images within a directory:
To implement a for loop:
for file in `ls original/image/path/`;
    do new_path=${file%.*};
    new_file=`basename $new_path`;
    convert $file -resize 150 conerted/image/path/$new_file.png;
done
''',

########## dd ################################################################
'dd' : '''
@todo
''',

########## dhclient ##########################################################
'dhclient' : '''
To release the current IP address:
sudo dhclient -r

To obtain a new IP address:
sudo dhclient

Running the above in sequence is a common way of refreshing an IP.
''',

########## find ##############################################################
'find' : '''
To find files by extension (ex: .jpg):
find . -iname "*.jpg"

To find directories:
find . -type d

To find files:
find . -type f

To find files by octal permission:
find . -type f -perm 777

To find files with setuid bit set:
find . -xdev \( -perm -4000 \) -type f -print0 | xargs -0 ls -l
''',

########## git ###############################################################
'git' : '''
To set your identify:
git config --global user.name "John Doe"
git config --global user.email johndoe@example.com

To enable color:
git config --global color.ui true
''',

########## ln ################################################################
'ln' : '''
To create a symlink:
ln -s path/to/the/target/directory name-of-symlink
''',

########## mysqldump #########################################################
'mysqldump' : '''
To dump a database to a file:
mysqldump -uusername -ppassword the-database > db.sql

To dump a database to a .tgz file:
mysqldump -uusername -ppassword the-database | gzip -9 > db.sql

To dump all databases to a file:
mysqldump -uusername -ppassword --all-databases > all-databases.sql
''',

########## netstat ###########################################################
'netstat' : '''
To view which users/processes are listening to which ports:
sudo netstat -lnptu
''',

########## notify-send #######################################################
'notify-send' : '''
To send a desktop notification via dbus:
notify-send -i 'icon-file/name' -a 'application_name' 'summary' 'body of message'

The -i and -a flags can be omitted if unneeded.
''',

########## sed ################################################################
'sed' : '''
To replace all occurrences of "day" with "night" and write to stdout:
sed s/day/night file.txt

To replace all occurrences of "day" with "night" within file.txt:
sed s/day/night file.txt > file.txt

To replace all occurrences of "day" with "night" on stdin:
echo 'It is daytime' | sed s/day/night/
''',

########## shred ##############################################################
'shred' : '''
To shred a file (5 passes) and verbose output:
shred -n 5 -v file.txt

To shred a file (5 passes) and a final overwrite of zeroes:
shred -n 5 -vz file.txt

To do the above, and then truncate and rm the file:
shred -n 5 -vzu file.txt

To shred a partition:
shred -n 5 -vz /dev/sda

Remember that shred may not behave as expected on journaled file systems if file data is being journaled.
''',

########## split #############################################################
'split' : '''
To split a large text file into smaller files of 1000 lines each:
split file.txt -l 1000

To split a large binary file into smaller files of 10M each:
split file.txt -b 10M

To consolidate split files into a single file: 
cat x* > file.txt
''',

########## sockstat ##########################################################
'sockstat' : '''
To view which users/processes are listening to which ports:
sudo sockstat -l
''',

########## ssh ###############################################################
'ssh' : '''
To execute a command on a remote server:
ssh -t user@example.com 'the-remote-command'

To tunnel an x session over SSH:
ssh -X user@example.com

To launch a specific x application over SSH:
ssh -X -t user@example.com 'chromium-browser'

For more information, see:
http://unix.stackexchange.com/q/12755/44856
''',

########## ssh-copy-id ########################################################
'ssh-copy-id' : '''
To copy a key to a remote host:
ssh-copy-id username@host

To copy a key to a remote host on a non-standard port:
ssh-copy-id username@host -p 2222
''',

########## ssh-keygen ########################################################
'ssh-keygen' : '''
To generate an SSH key:
ssh-keygen -t rsa

To generate a 4096-bit SSH key:
ssh-keygen -t rsa -b 4096

To copy a key to a remote host:
ssh-copy-id username@host

To copy a key to a remote host on a non-standard port:
ssh-copy-id username@host -p 2222
''',

########## stdout #############################################################
'stdout' : '''
To redirect stderr to stdout:
some-command 2>&1

To redirect stderr to a file
some-command 2> errors.txt
''',

########## tar ###############################################################
'tar' : '''
To extract an uncompressed archive: 
tar -xvf /path/to/foo.tar

To extract a .gz archive:
tar -xzvf /path/to/foo.tgz

To create a .gz archive:
tar -czvf /path/to/foo.tgz /path/to/foo/

To extract a .bz2 archive:
tar -xjvf /path/to/foo.tgz

To create a .bz2 archive:
tar -cjvf /path/to/foo.tgz /path/to/foo/
''',

}

# Cheatsheets can be aliased under a different keyphrase like this:
cheatsheets['dbus']        = cheatsheets['notify-send']
cheatsheets['imagick']     = cheatsheets['convert']
cheatsheets['redirection'] = cheatsheets['stdout']