Update DOCUMENTATION.md

Fix incorrect command.

Author: pierre-24

DOCUMENTATION.md

@@ -163,7 +163,7 @@ The procedure is more complex, since one needs the derivatives of the BORN charg
 phonopy-vs-prepare-raman
 
 # 2. Create folders for calculations
-for i in dielec-*.vasp; do a=$(i%.vasp); mkdir -p $a; cd $a; ln -s ../$i POSCAR; cd ..; done; 
+for i in dielec_*.vasp; do a=${i%.vasp}; mkdir -p $a; cd $a; ln -s ../$i POSCAR; cd ..; done; 
 
 # 3. Run calculations with `LEPSILON = .TRUE.` for each displaced geometry
 for i in dielec-*; do cd $i; vasp_std; cd ..; done
@@ -228,4 +228,4 @@ My name is [Pierre Beaujean](https://pierrebeaujean.net), and I have a Ph.D. in
 I'm the main (and only) developer of this project, used in our lab.
 I use this in the frame of my post-doctoral research in order to study batteries and solid electrolyte interphrase, and I developed this project to ease my life.
 
-Note: due to my (quantum) chemistry background, we may speak of similar things using a different vocabulary.
+Note: due to my (quantum) chemistry background, we may speak of similar things using a different vocabulary.