Shell tricks

tricks.sh

# Process files in a loop with arbitrary names
while IFS= read -r -d '' f; do
  cp "$f" /path2/
done < <(find /path/ -wholename '*.mp3' -print0)

# Find a pattern and replace in place using sed
ls /path/*.csv -1 | grep "subj[0-9]_" | sed -n "s/\(.*subj\)\([0-9].*\)/mv \1\2 \10\2/p"

# Count the number of files in each sub directory and write to a file
find images/ -maxdepth 1 -print0 | xargs -0 -n 1 -I dir sh -c 'printf dir"\t"; find dir/ -name "*.jpg" | wc -l' &> distribution.txt

# Count the number of files in each sub directory, check against a threshold and write to a file
find images/ -maxdepth 1 -print0 | xargs -0 -n 1 -I dir sh -c 'printf dir"\t"; find dir/ -name "*.jpg" | wc -l' | \
awk '{ split($0,a,"/"); split(a[2],b,"\t"); printf ($NF < 500) ? (b[1] != "") ? b[1]"\t"b[2]"\n" : "" : "" }'