linux wildcard usage in cp and mv

Let’s talk about how wildcards work for a minute.

cp *.txt foo

doesn’t actually invoke cp with an argument *.txt, if any files matching that glob exist. Instead, it runs something like this:

cp a.txt b.txt c.txt foo

Similarly, something like

mv *.txt *.old

…can’t possibly know what to do, because when it’s invoked, what it sees is:

mv a.txt b.txt c.txt *.old

or, worse, if you already have a file named z.old, it’ll see:

mv a.txt b.txt c.txt z.old

Thus, you need to use different tools. Consider:

# REPLACES: mv /data/*/Sample_*/logs/*_Data_time.err /data/*/Sample_*/logs/*_Data_time_orig.err
for f in /data/*/Sample_*/logs/*_Data_time.err; do
  mv "$f" "${f%_Data_time.err}_Data_time_orig.err"
done

# REPLACES: cp /data/*/Sample_*/scripts/*.sh /data/*/Sample_*/scripts/*_orig.sh
for f in /data/*/Sample_*/scripts/*.sh; do
  cp "$f" "${f%.sh}_orig.sh"
done

# REPLACES: sh /data/*/Sample_*/scripts/*_orig.sh
for f in /data/*/Sample_*/scripts/*_orig.sh; do
  if [[ -e "$f" ]]; then
    # honor the script's shebang and let it choose an interpreter to use
    "$f"
  else
    # script is not executable, assume POSIX sh (not bash, ksh, etc)
    sh "$f"
  fi
done

This uses a parameter expansion to strip off the tail end of the old name before adding the new name.