#Linux rights

Rights r w x
Owner 400 200 100
Group 40 20 10
Others 4 2 1

#find jpg mv

find . -name "*.jpg" -exec mv {} . \;

#Search & Replace in files with command-line (-name optional)

find . -name *.php -exec sed -i s@require_once@//require_once@g {} \;

#applying a patch

Place the .diff file in the same directory as the source tarball. Ungzip/untar the source, and run

patch -p0 < some-patch-file.diff

The -p0 indicates the paths in the file are relative to the current directory, if you place the .diff file in the some-soft-source dir you need -p1.

#Remove orphaned configuration files

# aptitude purge $(dpkg --get-selections | grep deinstall | awk '{print $1}')

#List the files with a different MD5 checksum

find . -maxdepth 1 -type f -print0 | xargs -0 md5sum | sort | uniq -w 32 | awk '{print $2}' > ./distinct.txt

#pdf to jpg

Each page as an image :

convert file.pdf image%d.jpg

#grep

dpkg -l | grep '(15|16)' | grep linux

#multiple egrep

cat file.txt | egrep -i '(pattern1|pattern2)'

#optimise firefox sqlite

find ~/.mozilla/firefox/ -type f -name "*.sqlite" -exec sqlite3 {} VACUUM \;

#cp dir1 > dir2

cp -ruv /dir1/ /dir2/

The options allow you to display the copied files, copy entire directories, and update files that have already been copied.

#list dir

find . -type d

#cpu load in %

top -b -n 1 | grep Cpu | awk '{print $2}' | cut -c1-4

#capture tty

fbgrab capture.png

#add a word to the beginning of each line

for i in `cat file.txt` ; do word_to_add $i ; done

#cat without duplicate

cat file1.txt file2.txt | sort -n | uniq -u

#extract only the parts that are "readable" with strings

strings file.doc | less

and

strings -e b file.doc | less

#iso to utf

iconv -f ISO-8859-1 -t UTF-8 -o output.txt input.txt
iconv -f UTF-8 -t ISO-8859-1 -o output.txt input.txt
recode ISO-8859-15..UTF-8 input.txt

#sum with awk

For example, to determine the amount of memory being used by process apache2:

ps -ely | grep '\<apache2\>' | awk '{SUM += $8} END {print SUM}'

or to find out the total size in kilobytes occupied by all the PNG files in the directory:

ls -l *.png | awk '{SUM += $5} END {print SUM/1024}'

#Displays the most recent file .txt

ls -t1 *.txt | head -1

#Displays all .txt files except for the file named "file.txt"

ls *.txt | grep -v file.txt | xargs ls

#Display all .txt files except for the last .txt file

ls *.txt | grep -v `ls -t1 *.txt | head -1`

#sed syntax for displaying the text between "pattern1" and "pattern2":

sed -n '/pattern1/,/pattern2/p' /path/to/file

#Keyboard shortcuts for Bash

Some of these commands also work within command-line file editors. For example, Emacs offers movement commands and copy/paste functionality

1. Move

Ctrl + a: Go to the beginning of the line

Ctrl + e: Go to the end of the line

Alt + b: Move word by word backward in the command line (b for backward)

Alt + f: Move word by word forward in the command line (f for forward)

Ctrl + xx: Position the cursor at the beginning or end of the word

2. Cut/Paste

Ctrl + k: Cut the string from the cursor to the end of the line

Ctrl + u: Cut the string from the cursor to the beginning of the line

Ctrl + w: Cut the word before the cursor

Ctrl + y: Paste a string

3. Modification

Ctrl + t: swap the position of the two characters before the cursor (useful when typing, for example, sl instead of ls)

Alt + t: swap the position of the two words before the cursor

Alt + c: capitalize a letter

Alt + l: convert a word to lowercase (l for lowercase)

Alt + u: capitalize a word (u for uppercase)

Alt + .: rewrite the parameter of the last command

4. Miscellaneous

Ctrl + l: Clear the screen

Ctrl + r: Search for a previously typed command

Ctrl + -: Undo the last change

Ctrl + c: Stop the current command

Ctrl + d: Exit the current shell