bash :: Enum files

IDX=0 ; for TMP in $(ls) ; do IDX=$(($IDX+1)) ; cp $TMP $IDX.ext ; done

bash :: Resize with orig aspect to max size [Source]

for TMP in *jpg ; do convert $TMP -resize 640x400\> 640_$TMP ; done

bash :: String manipulation, String Operators

TMP2=${TMP1// /_}       # replace sed 's/ /_/g' 
TMP2=${TMP1:1}          # remove first char of TMP1
TMP2=${TMP1::-1}        # remove last char of TMP1
TMP2=${TMP1##*:}        # last element of string (separator :)
TMP2=${TMP1/*foo*/}     # if foo is not substring of TMP1, then TMP2 is empty

bash :: convert filenames from iso to utf8

detox -nrv -s iso8859_1 directory/

bash :: send message to xfce desktop

notify-send "Header" "Text of message"   # as X user
su $USER -c 'DISPLAY=:0 notify-send "Header" "Text of message"'   # as root

bash :: div snippets

for i in $(seq 701 726) ; do echo "$i "; done >> s7.txt # numbering