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Date:      Wed, 19 Jul 1995 14:22:50 -0600 (MDT)
From:      Ade Barkah <mbarkah@hemi.com>
To:        hackers@freebsd.org
Subject:   Being curious with `cat * > file'
Message-ID:  <199507192022.OAA10037@hemi.com>

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Hello,

What should `cat * > output` do ? Should it gracefully concatenate
all the files together into a file called `output', or will it
attempt to cat the output into itself so many times until the
file system is filled ?

In FreeBSD 2.0.5-950622-SNAP, the results are somewhat random:
sometimes graceful, other times it fills up the file system.
Is this a bug, feature, or is doing `cat * > output` considered
an error ?

The "problem" appears on two 2.0.5 machines here.

Here's a sample session:

[The particular shell is tcsh in my home directory. However,
I can reproduce the problem with /bin/csh in /root (say, I 
just logged in as root.)]

barkah: {1} mkdir test1
barkah: {2} cd test1
barkah: {3} cat >> testfile <<!
test file
barkah: {4} cat * > output
barkah: {5} ls -l
total 4
-rw-rw-r--  1 mbarkah  userm  10 Jul 19 13:50 output
-rw-rw-r--  1 mbarkah  userm  10 Jul 19 13:50 testfile

[Looks great up to this point, works as expected]

barkah: {6} cat * > output2

[Job killed with ctrl-c at this point]

barkah: {7} ls -l
total 916
-rw-rw-r--  1 mbarkah  userm      10 Jul 19 13:50 output
-rw-rw-r--  1 mbarkah  userm  454360 Jul 19 13:50 output2
                              ^^^^^^
-rw-rw-r--  1 mbarkah  userm      10 Jul 19 13:50 testfile

[Look how huge that output2 file is!]

barkah: {8} tail -5 output2
test file
test file
test file
test file
test file

[And now for some random info]

barkah: {9} uname -a
FreeBSD barkah.hemi.com 2.0.5-950622-SNAP FreeBSD 2.0.5-950622-SNAP #0: Wed Jul 
12 19:10:26 MDT 1995     root@barkah.hemi.com:/usr/src/sys/compile/KERNEL  i386
barkah: {10} df -k .
Filesystem   1K-blocks     Used    Avail Capacity  Mounted on
/dev/sd1s1f    1523098   533437   867813    38%    /usr2
barkah: {11} grep usr2 /etc/fstab
/dev/sd1s1f			/usr2		ufs	rw 1 1
barkah: {12} dmesg | grep aha0:1:0
(aha0:1:0): "HP 2.13 GB #A1 9002" type 0 fixed SCSI 2
sd1(aha0:1:0): Direct-Access 2033MB (4165272 512 byte sectors)


Thanks for any ideas,

-Ade Barkah
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