diff --git a/lib/spack/spack/cmd/buildcache.py b/lib/spack/spack/cmd/buildcache.py
index 05b7bd783a..76e2d0f61c 100644
--- a/lib/spack/spack/cmd/buildcache.py
+++ b/lib/spack/spack/cmd/buildcache.py
@@ -188,14 +188,16 @@ def setup_parser(subparser: argparse.ArgumentParser):
         default=lambda: spack.config.default_modify_scope(),
         help="configuration scope containing mirrors to check",
     )
-    check_spec_or_specfile = check.add_mutually_exclusive_group(required=True)
-    check_spec_or_specfile.add_argument(
+    # Unfortunately there are 3 ways to do the same thing here:
+    check_specs = check.add_mutually_exclusive_group()
+    check_specs.add_argument(
         "-s", "--spec", help="check single spec instead of release specs file"
     )
-    check_spec_or_specfile.add_argument(
+    check_specs.add_argument(
         "--spec-file",
         help="check single spec from json or yaml file instead of release specs file",
     )
+    arguments.add_common_arguments(check, ["specs"])
 
     check.set_defaults(func=check_fn)
 
@@ -813,15 +815,24 @@ def check_fn(args: argparse.Namespace):
     exit code is non-zero, then at least one of the indicated specs needs to be rebuilt
     """
     if args.spec_file:
+        specs_arg = (
+            args.spec_file if os.path.sep in args.spec_file else os.path.join(".", args.spec_file)
+        )
         tty.warn(
             "The flag `--spec-file` is deprecated and will be removed in Spack 0.22. "
-            "Use --spec instead."
+            f"Use `spack buildcache check {specs_arg}` instead."
         )
+    elif args.spec:
+        specs_arg = args.spec
+        tty.warn(
+            "The flag `--spec` is deprecated and will be removed in Spack 0.23. "
+            f"Use `spack buildcache check {specs_arg}` instead."
+        )
+    else:
+        specs_arg = args.specs
 
-    specs = spack.cmd.parse_specs(args.spec or args.spec_file)
-
-    if specs:
-        specs = _matching_specs(specs)
+    if specs_arg:
+        specs = _matching_specs(spack.cmd.parse_specs(specs_arg))
     else:
         specs = spack.cmd.require_active_env("buildcache check").all_specs()
 
diff --git a/share/spack/spack-completion.bash b/share/spack/spack-completion.bash
index a54f7db414..cebf865d9e 100755
--- a/share/spack/spack-completion.bash
+++ b/share/spack/spack-completion.bash
@@ -618,7 +618,12 @@ _spack_buildcache_preview() {
 }
 
 _spack_buildcache_check() {
-    SPACK_COMPREPLY="-h --help -m --mirror-url -o --output-file --scope -s --spec --spec-file"
+    if $list_options
+    then
+        SPACK_COMPREPLY="-h --help -m --mirror-url -o --output-file --scope -s --spec --spec-file"
+    else
+        _all_packages
+    fi
 }
 
 _spack_buildcache_download() {
diff --git a/share/spack/spack-completion.fish b/share/spack/spack-completion.fish
index 1d32fc1d37..5d443c8b6d 100755
--- a/share/spack/spack-completion.fish
+++ b/share/spack/spack-completion.fish
@@ -797,6 +797,7 @@ complete -c spack -n '__fish_spack_using_command buildcache preview' -s h -l hel
 
 # spack buildcache check
 set -g __fish_spack_optspecs_spack_buildcache_check h/help m/mirror-url= o/output-file= scope= s/spec= spec-file=
+complete -c spack -n '__fish_spack_using_command_pos_remainder 0 buildcache check' -f -k -a '(__fish_spack_specs)'
 complete -c spack -n '__fish_spack_using_command buildcache check' -s h -l help -f -a help
 complete -c spack -n '__fish_spack_using_command buildcache check' -s h -l help -d 'show this help message and exit'
 complete -c spack -n '__fish_spack_using_command buildcache check' -s m -l mirror-url -r -f -a mirror_url