1. Remove leading zeros
num=0004; num=$(expr $num + 0) echo $num; # output: 4
2. subtract integers
num=3; subtract=50; numNew=$(( $num - $subtract)); echo $numNew; #result: -47
3. divide
num_half=$(expr $num / 2)
In the following some useful bash snippets to manipulat strings / file names are listed.
Extract substrings
1. crop a consecutive substring ${string:position:length}
name=abcd123FGHI;
subStr=${name:4:3};
echo $subStr; # result is 123
2. remove beginning or end of a string
str=/path/to/my/file/123_complicated_9034.txt;
removes shortest matching suffix pattern %
I included following lines into my ~/.bashrc to have a more secure shell experience.
1) Do not remove (unlink) a file, but move it to the trash-can. You have to install trash-cli,
sudo apt-get install trash-cli
alias rm="echo 'NOTE: !! not removing, but moving to trash-can!! '; trash-put"
If you want to use the normal rm command, use
/bin/rm file1ToRemove.txt file2ToRemove.png
2) ask before overwriting a file, if you accidentaly copy or move a file with the same name.
A list with examplary parameters of how to use the terminal function "find" (in Linux). This function can be used to find files, directories, etc. First open the terminal (Ctrl+Alt+t) and then type in one of the following commands.
| COMMAND | DESCRIPTION |
|
find /path/where/to/find -name "my_img.png" |
To install drupal on a hosted webserver follow this very good introduction.
During setting up I had two problems
PROBLEM 1) The directory sites/default/files does not exist . An automated attempt to create this directory failed, possibly due to a permissions problem.
SOLUTION: