shell 判断文件是否存在，-e or -f ?

Sometimes, we have met issue how to check whether one file exists using shell script.

you use "-e" or "-f" ? the two of them have some different which may mislead you if you don't know their exact usage.

-f filename

Return true filename exists and is a regular file, not including link file, directory, block special, character special

-e filename

Return true filename exists (regardless of type).

"regular file", as most UNIX/POSIX docs refer generically to all types of file system entries a simply "files", e.g., a symbolic link is a type of a file, as is a named pipe, regular file, directory, block special, character special, socket, et(转https://www.cyberciti.biz/tips/find-out-if-file-exists-with-conditional-expressions.html)

So, you see -e might stop you making mistakes.

 

Append the full list to check file exist.

[ Expression ]	Meaning
-b filename	Return true if filename is a block special file.
-c filename	Return true if filename exists and is a character special file.
-d filename	Return true filename exists and is a directory.
-e filename	Return true filename exists (regardless of type).
-f filename	Return true filename exists and is a regular file.
-g filename	Return true filename exists and its set group ID flag is set.
-h filename	Return true filename exists and is a symbolic link. This operator is retained for compatibility with previous versions of this program. Do not rely on its existence; use -L instead.
-k filename	Return true filename exists and its sticky bit is set.
-n filename	Return true the length of string is nonzero.
-p filename	Return true filename is a named pipe (FIFO).
-r filename	Return truefilename exists and is readable.
-s filename	Return true filename exists and has a size greater than zero.
-t file_descriptor	Return true the filename whose file descriptor number is file_descriptor is open and is associated with a terminal.
-u filename	Return true filename exists and its set user ID flag is set.
-w filename	Return true filename exists and is writable. True indicates only that the write flag is on. The file is not writable on a read-only file system even if this test indicates true.
-x filename	Return true filename exists and is executable. True indicates only that the execute flag is on. If file is a directory, true indicates that file can be searched.
-z string	Return true the length of string is zero.
-L filename	Return true filename exists and is a symbolic link.
-O filename	Return true filename exists and its owner matches the effective user id of this process.
-G filename	Return true filename exists and its group matches the effective group id of this process.
-S filename	Return true filename exists and is a socket.
file1 -nt file2	True if file1 exists and is newer than file2.
file1 -ot file2	True if file1 exists and is older than file2.
file1 -ef file2	True if file1 and file2 exist and refer to the same file.