Check if file exists [SH] [duplicate] - linux

Question

This question already has answers here:
Meaning of "[: too many arguments" error from if [] (square brackets)
(6 answers)
Closed 5 years ago.
I created a script that will check for the existence of .gz files in the base directory and if it finds them it moved them into a new structure based on the current date. The script works perfectly when the shell is set to /bin/bash and I run it manually, but this script is run as a cron job (by logrotate) and I believe that it MUST be run under /bin/sh as I am not sure how to get logrotate to run it under /bin/bash. The code in question is
# Move rotated logs to the archive
if [ -f $BASEDIR/*.gz ]; then
logger "$SNAME Moving rotated logs to $DIRECTORY"
mv $BASEDIR/*.gz $DIRECTORY
else
echo "$BASEDIR/*.gz"
logger "$SNAME No rotated logs to move. Is this normal?"
fi
In bash the conditional check works great, under sh it complains there are too many arguments. If I put things in quotes it doesn't see the wildcard and aways returns false.
Any help would be fantastic!

Answer 1

The problem here is that [ -f pathname ] takes exactly one name ([ -f one.gz two.gz ] isn't valid test syntax), but you don't know how many names *.gz expands to.
check() {
set -- "$BASEDIR"/*.gz
if [ -f "$1" ] || [ -L "$1" ]; then
logger "$SNAME Moving rotated logs to $DIRECTORY"
mv -- "$#" "$DIRECTORY"
else
echo "$BASEDIR/*.gz"
logger "$SNAME No rotated logs to move. Is this normal?"
fi
}
check
Breaking this down:
check() { ... } defines a function named check, which we then call later.
set -- "$BASEDIR"/*.gz replaces the function's argument list (this is why we're using a function, so we don't overwrite the whole script's argument list!) with a list of files with names ending in *.gz.
[ -f "$1" ] tests if the first name in this list exists -- if it does, then we know that the expansion was successful. [ -L "$1" ] can also be true if the glob successfully expanded but the first entry was a symlink to a file that doesn't exist; by including it, we cover that corner case.
mv -- "$#" "$DIRECTORY" reuses that argument list to pass to mv. The -- argument specifies to mv that all following arguments are names, even if they start with -s.

Answer 2

How about this:
if ls "$BASEDIR"/*.gz
then
echo "moving them ..."
else
echo "No such file!"
fi