Shell script to count files, then remove oldest files

Question

I am new to shell scripting, so I need some help here. I have a directory that fills up with backups. If I have more than 10 backup files, I would like to remove the oldest fi

Answer 1

On a very limited chroot environment, we had only a couple of programs available to achieve what was initially asked. We solved it that way:

MIN_FILES=5
FILE_COUNT=$(ls -l | grep -c ^d )


if [ $MIN_FILES -lt $FILE_COUNT  ]; then
  while [ $MIN_FILES -lt $FILE_COUNT ]; do
    FILE_COUNT=$[$FILE_COUNT-1]
    FILE_TO_DEL=$(ls -t | tail -n1)
    # be careful with this one
    rm -rf "$FILE_TO_DEL"
  done
fi

Explanation:

• FILE_COUNT=$(ls -l | grep -c ^d ) counts all files in the current folder. Instead of grep we could use also wc -l but wc was not installed on that host.
• FILE_COUNT=$[$FILE_COUNT-1] update the current $FILE_COUNT
• FILE_TO_DEL=$(ls -t | tail -n1) Save the oldest file name in the $FILE_TO_DEL variable. tail -n1 returns the last element in the list.