# Linux singer 6.6.37-0-lts x86_64
# /dev/shm and /tmp are tmpfs
# as user, nsm here:
#   touch /dev/shm/mempool.dat.new
# as root:
#   cd /home/nsm/.bitcoin
#   mount -o rw,bind /dev/shm/mempool.dat.new mempool.dat.new
# everything else here that follows
# is run as an unprivileged user
+ date -u
Fri Mar 14 11:15:00 UTC 2025
+ + bitcoindhead -1 -version

Bitcoin Core version v28.1.0
+ bitcoin-cli echo hello
+ grep .
[
  "hello"
]
+ mountpoint /home/nsm/.bitcoin/mempool.dat.new
/home/nsm/.bitcoin/mempool.dat.new is a mountpoint
+ bitcoin-cli getmempoolinfo
+ nicecat.sh /tmp/gmi-main.json
{
  "loaded": true,
  "size": 15089,
  "bytes": 19936771,
  "usage": 101424000,
  "total_fee": 0.26642948,
  "maxmempool": 500000000,
  "mempoolminfee": 0.00001000,
  "minrelaytxfee": 0.00001000,
  "incrementalrelayfee": 0.00001000,
  "unbroadcastcount": 0,
  "fullrbf": true
}
+ : following is getrawmempool, just shortened
+ grm.sh
+ safecat.sh /dev/shm/mymempool.txt
+ : Following non-zero exit is intended.
+ : On bitcoind side it looks like this:
+ : Failed to dump mempool: Rename failed. Continuing anyway.
+ time bitcoin-cli savemempool
error code: -1
error message:
Unable to dump mempool to disk
Command exited with non-zero status 1
real	0m 0.65s
user	0m 0.00s
sys	0m 0.00s
+ f=/dev/shm/mempool.dat.new
+ t=/dev/shm/mempool.dat.tmp
+ cp /dev/shm/mempool.dat.new /dev/shm/mempool.dat.tmp
+ : UNIX fixes this, file descriptor stays
+ : i n memory when used even after file was
+ : successfully unlinked from filesystem
+ : GNU is Not Unix anyway
+ mv /dev/shm/mempool.dat.tmp /dev/shm/mempool.copy
+ cd /dev/shm
+ ls -ilh mempool.copy mempool.dat.new
1074335 -rw-r--r-- 1 nsm nsm 36M Mar 14 11:15 mempool.copy
 183442 -rw-r--r-- 1 nsm nsm 36M Mar 14 11:15 mempool.dat.new
+ cd /home/nsm/web/ln
+ ls -l mymempool-log.txt mymempool.dat mymempool.txt
lrwxrwxrwx 1 nsm nsm 22 Feb 21 13:10 mymempool-log.txt -> /dev/shm/mymempool.log
lrwxrwxrwx 1 nsm nsm 21 Dec 10 12:10 mymempool.dat -> /dev/shm/mempool.copy
lrwxrwxrwx 1 nsm nsm 22 Feb 18 11:10 mymempool.txt -> /dev/shm/mymempool.txt
+ date -u
Fri Mar 14 11:15:01 UTC 2025