remove useless echo

Author: marcoieni

src/ci/scripts/free-disk-space.sh

@@ -15,11 +15,15 @@ printSeparationLine() {
 # compute available space
 # REF: https://unix.stackexchange.com/a/42049/60849
 # REF: https://stackoverflow.com/a/450821/408734
-getAvailableSpace() { echo $(df -a | awk 'NR > 1 {avail+=$4} END {print avail}'); }
+getAvailableSpace() {
+    df -a | awk 'NR > 1 {avail+=$4} END {print avail}'
+}
 
 # make Kb human readable (assume the input is Kb)
 # REF: https://unix.stackexchange.com/a/44087/60849
-formatByteCount() { echo $(numfmt --to=iec-i --suffix=B --padding=7 $1'000'); }
+formatByteCount() {
+    numfmt --to=iec-i --suffix=B --padding=7 $1'000'
+}
 
 # macro to output saved space
 printSavedSpace() {