STYLE: remove unnecessary stdout, stderr /dev/null redirects

- no stderr redirect needed:
    * 'command -v'

- no stdout/stderr redirect needed:
    * 'rm -f'

STYLE: consistent spacing after redirects

tutorials/discreteMethods/dsmcFoam/freeSpaceStream/Allclean

@@ -5,6 +5,6 @@ cd ${0%/*} || exit 1                                # Run from this directory
 
 cleanCase
 
-rm -rf 0/lagrangian 0/dsmcSigmaTcRMax 0/uniform > /dev/null 2>&1
+rm -rf 0/lagrangian 0/dsmcSigmaTcRMax 0/uniform
 
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