TP 2.2: Find files and control data access

Goal: Find and protect data.

You did some manipulation on files in TP 2.1 and you want to be sure that nobody on the cluster can access your data. Answer the questions to deny access to others.

Search for files

Question

From your home directory, search the files named ab*.fasta with find command.

Display help in order to find the option that search into save and work directories that are symbolic links.

Solution

First try:

cd
find . -name "ab*.fasta"

It display nothing, which is not what we expected. Then we check the manual:

man find

Finally, we use the right option:

find -L . -name "ab*.fasta"

Search files by criterion

Question

From the directory ~/save/tp_unix, search files with size greater than 100KB.

Solution

cd ~/save/tp_unix
find . -size +100k

Manage read permissions

Question

In the same directory ~/save/tp_unix, remove the everyone's read permission from the directory data.

Can you list the content of data ?

Add yourself back the read permission (r) on this directory.

Solution

chmod a-r data
ls data
chmod u+r data

Manage execution/traversal permissions

Question

Remove everyone's execution permission from directory data.

Could you enter inside the directory data?

Add yourself back the execution permission (x) on this directory. The execussion access on a directory allows traverval of this directory.

Solution

chmod a-x data
cd data
chmod u+x data