当我运行rustup update时，我收到以下错误：
info: syncing channel updates for 'stable-x86_64-unknown-linux-gnu'
error: could not create temp file /home/abc/.rustup/tmp/mbbafo7rtfs5aazi_file
info: checking for self-updates
stable-x86_64-unknown-linux-gnu update failed - rustc 1.52.1 (9bc8c42bb 2021-05-09)
info: cleaning up downloads & tmp directories
thread 'main' panicked at 'Unable to clean up /home/abc/.rustup/downloads: Os { code: 13, kind: PermissionDenied, message: "Permission denied" }', src/utils/utils.rs:642:13
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
然后，我尝试运行sudo rustup update并得到以下信息：
sudo: rustup: command not found
的输出ls -l /home/abc/.rustup/是：
total 28
drwxr-xr-x 2 root root 4096 May 31 14:06 downloads
-rw-r--r-- 1 root root 102 May 31 14:06 settings.toml
drwxr-xr-x 2 root root 4096 May 31 14:06 tmp
drwxr-xr-x 3 root root 4096 May 31 14:06 toolchains
drwxr-xr-x 2 root root 4096 May 31 14:06 update-hashes