Make shellcheck fixes for ush script

Refs: #761

ush/wave_prnc_cur.sh

@@ -36,32 +36,32 @@ fext='f'
 mkdir -p rtofs_${ymdh_rtofs}
 cd rtofs_${ymdh_rtofs}
 
-ncks -x -v sst,sss,layer_density  $curfile cur_uv_${PDY}_${fext}${fh3}.nc
-ncks -O -a -h -x -v Layer cur_uv_${PDY}_${fext}${fh3}.nc cur_temp1.nc
+ncks -x -v sst,sss,layer_density "${curfile} cur_uv_${PDY}_${fext}${fh3}.nc"
+ncks -O -a -h -x -v Layer "cur_uv_${PDY}_${fext}${fh3}.nc" "cur_temp1.nc"
 ncwa -h -O -a Layer cur_temp1.nc cur_temp2.nc
 ncrename -h -O -v MT,time -d MT,time cur_temp2.nc
 ncks -v u_velocity,v_velocity cur_temp2.nc cur_temp3.nc
-mv -f cur_temp3.nc cur_uv_${PDY}_${fext}${fh3}_flat.nc
+mv -f "cur_temp3.nc" "cur_uv_${PDY}_${fext}${fh3}_flat.nc"
 
 # Convert to regular lat lon file
 # If weights need to be regenerated due to CDO ver change, use:
 # $CDO genbil,r4320x2160 rtofs_glo_2ds_f000_3hrly_prog.nc weights.nc
 cp ${FIXwave}/weights_rtofs_to_r4320x2160.nc ./weights.nc
 
 # Interpolate to regular 5 min grid
-$CDO remap,r4320x2160,weights.nc cur_uv_${PDY}_${fext}${fh3}_flat.nc cur_5min_01.nc
+${CDO} remap,r4320x2160,weights.nc "cur_uv_${PDY}_${fext}${fh3}_flat.nc" "cur_5min_01.nc"
 
 # Perform 9-point smoothing twice to make RTOFS data less noisy when
 # interpolating from 1/12 deg RTOFS grid to 1/6 deg wave grid
 if [ "WAV_CUR_CDO_SMOOTH" = "YES" ]; then
-  $CDO -f nc -smooth9 cur_5min_01.nc cur_5min_02.nc
-  $CDO -f nc -smooth9 cur_5min_02.nc cur_glo_uv_${PDY}_${fext}${fh3}_5min.nc
+  ${CDO} -f nc -smooth9 "cur_5min_01.nc" "cur_5min_02.nc"
+  ${CDO} -f nc -smooth9 "cur_5min_02.nc" "cur_glo_uv_${PDY}_${fext}${fh3}_5min.nc"
 else
-  mv cur_5min_01.nc cur_glo_uv_${PDY}_${fext}${fh3}_5min.nc
+  mv "cur_5min_01.nc" "cur_glo_uv_${PDY}_${fext}${fh3}_5min.nc"
 fi
 
 # Cleanup
-rm -f cur_temp[123].nc cur_5min_??.nc cur_glo_uv_${PDY}_${fext}${fh3}.nc weights.nc
+rm -f cur_temp[123].nc cur_5min_??.nc "cur_glo_uv_${PDY}_${fext}${fh3}.nc weights.nc"
 
 if [ ${flagfirst}  = "T" ]
 then
@@ -71,8 +71,8 @@ else
 fi
 
 rm -f cur.nc
-ln -s cur_glo_uv_${PDY}_${fext}${fh3}_5min.nc cur.nc
-ln -s ${DATA}/mod_def.${WAVECUR_FID} ./mod_def.ww3
+ln -s "cur_glo_uv_${PDY}_${fext}${fh3}_5min.nc" "cur.nc"
+ln -s "${DATA}/mod_def.${WAVECUR_FID}" ./mod_def.ww3
 
 export pgm=ww3_prnc;. prep_step
 $EXECwave/ww3_prnc 1> prnc_${WAVECUR_FID}_${ymdh_rtofs}.out 2>&1