New comment by Anachron on mblaze repository

https://github.com/leahneukirchen/mblaze/issues/184#issuecomment-820924647

Comment:
Hey @sucrecacao this might be a bit late, but I compose messages with `mcom` and then send them via `msmtp`. 
I use a few wrapper scripts to change my `mblaze` & `msmtp` default account. 

mfrom
```
test "$#" -eq 0 && awk -F ':' '$1 == "Local-Mailbox" {print $2}' ~/.mblaze/profile | xargs && exit
acc=$(sed -n "/^account[ ]*${1}$/,/^$/p" ~/.msmtprc | awk '$1 == "from" {print $2}')
if test -n "${acc}"; then
  sed -i "s|^Local-Mailbox.*|Local-Mailbox: ${acc}|" ~/.mblaze/profile
  sed -i "s|^Outbox.*|Outbox: ${HOME}/usr/mls/${1}/OUTBOX|" ~/.mblaze/profile
  ! test -e ~/.mblaze/signature || rm ~/.mblaze/signature
  ! test -f "${HOME}/usr/mls/${1}/signature" || ln -s "${HOME}/usr/mls/${1}/signature" ~/.mblaze/signature
  sed -i "s|account default.*|account default: ${1}|" ~/.msmtprc
  printf 'Switched to "%s"\n' "${acc}"
fi
```