An alias can not take arguments and use $@ to access them like that.
Alias expansion in bash is a simple text replacement. If you have alias rm ='something something', then using rm file1 file2 would execute
something something file1 file2
and if the alias included $@, this would be expanded with the command line arguments of the shell, not of the alias.
In your case, assuming the shell's list of command line arguments is empty, the alias
alias rm='cp $@ /tmp/recycle_bin && rm $@'
would execute as
cp /tmp/recycle_bin && rm file1 file2
when invoked as rm file1 file2. The cp utility will complain about only having a single operand.
You could use a shell function instead:
rm () {
cp -- "$@" "${TMPDIR:-/tmp}/recycle_bin" &&
command rm -- "$@"
}
This would copy the indicated files to $TMPDIR/recycle_bin (or /tmp/recycle_bin if TMPDIR is unset or empty) and then delete the files. The command command is used to not cause an infinite recursion. The -- are needed to treat all arguments as filenames rather than as options. Note also that the quoting is important so that filenames are not split on whitespaces and so that filename globbing patterns in the arguments are not picking up files that you don't want to remove.
A bit more efficient (cp+rm == mv):
rm () {
mv -- "$@" "${TMPDIR:-/tmp}/recycle_bin"
}
A bit more safe (creates the recycle bin if it's not there):
rm () {
mkdir -p "${TMPDIR:-/tmp}/recycle_bin" &&
mv -- "$@" "${TMPDIR:-/tmp}/recycle_bin"
}
And even safer, with GNU mv (creates backups in the recycle bin if name collisions occur):
rm () {
mkdir -p "${TMPDIR:-/tmp}/recycle_bin" &&
mv -b -- "$@" "${TMPDIR:-/tmp}/recycle_bin"
}
For an alias-only (and GNU-only) variation, see "https://unix.stackexchange.com/questions/452496".