While studying for the RHCE, I came across a situation where stdin redirection does not work in bash:

# file /tmp/users.txt
/tmp/users.txt: cannot open `/tmp/users.txt' (No such file or directory)  
# semanage login -l > /tmp/users.txt
# file /tmp/users.txt
/tmp/users.txt: empty

However, this works:

# file /tmp/users.txt
/tmp/users.txt: cannot open `/tmp/users.txt' (No such file or directory)
# semanage login -l >> /tmp/users.txt
# file /tmp/users.txt
/tmp/users.txt: ASCII text

Why is this the case?

Update:

Permissions:

# ls -ld /tmp
drwxrwxrwt. 8 root root 4096 Jul 17 15:27 /tmp

ACLs (not an ACL mount but just in case):

# getfacl /tmp
getfacl: Removing leading '/' from absolute path names
# file: tmp
# owner: root
# group: root
# flags: --t
user::rwx
group::rwx
other::rwx

And I'm performing all commands as root (hence the bang prompt).