can use it. Disconnecting master all future attempts to connect
from the script will fail.
+At the end of this document there is information for some possible ways
+how master ssh connection can be done.
+
## The script
Write the following code to a file, for example `remote-notmuch.sh`.
- #!/bin/bash
+ #!/bin/bash
- # http://notmuchmail.org/remoteusage/aboriginal/
+ # http://notmuchmail.org/remoteusage/aboriginal/
- set -eu
+ set -eu
+ # To trace execution, outcomment next line. Note that emacs input may ...
+ #exec 2>>remote-errors; echo -- >&2; set -x # ... change (no stderr).
- readonly SSH_CONTROL_SOCK='~'/.ssh/master-user@host:22
+ readonly SSH_CONTROL_SOCK='~'/.ssh/master-user@host:22
- readonly notmuch=notmuch
+ readonly notmuch=notmuch
- printf -v ARGS '%q ' "$@" # bash feature
+ printf -v ARGS '%q ' "$@" # bash feature
- readonly SSH_CONTROL_ARGS='-oControlMaster=no -S '$SSH_CONTROL_SOCK
+ readonly SSH_CONTROL_ARGS='-oControlMaster=no -S '$SSH_CONTROL_SOCK
- if ssh $SSH_CONTROL_ARGS 0.1 $notmuch $ARGS 2>>/dev/null
- then exit 0
- else ev=$?
- fi
+ if ssh -q $SSH_CONTROL_ARGS 0.1 $notmuch $ARGS
+ then exit 0
+ else ev=$?
+ fi
- # continuing here in case ssh exited with nonzero value.
+ # continuing here in case ssh exited with nonzero value.
- case $* in
- 'config get user.primary_email') echo 'nobody@nowhere.invalid'; exit 0 ;;
- 'config get user.name') echo 'nobody'; exit 0 ;;
- 'count'*) echo 1; exit 0 ;;
- 'search-tags'*) echo 'errors'; exit 0 ;;
- 'search'*'--output=tags'*) echo 'errors'; exit 0 ;;
- esac
+ case $* in
+ 'config get user.primary_email') echo 'nobody@nowhere.invalid'; exit 0 ;;
+ 'config get user.name') echo 'nobody'; exit 0 ;;
+ 'count'*'--batch'*) while read line; do echo 1; done; exit 0 ;;
+ 'count'*) echo 1; exit 0 ;;
+ 'search-tags'*) echo 'errors'; exit 0 ;;
+ 'search'*'--output=tags'*) echo 'errors'; exit 0 ;;
+ esac
- if ssh $SSH_CONTROL_ARGS -O check 0.1
- then
- echo ' Control socket is alive but something failed during data transmission.'
- exit $ev
- fi
+ if ssh $SSH_CONTROL_ARGS -O check 0.1
+ then
+ echo ' Control socket is alive but something failed during data transmission.'
+ exit $ev
+ fi
- echo " See`sed '1d;2d;s/.//;q' "$0"` for help."
+ echo " See`sed '1d;2d;s/.//;q' "$0"` for help."
Note the `0.1` in ssh command line. It is used to avoid any opportunistic
behaviour ssh might do; for example if control socket is not alive ssh
Easiest way to test this script is to run the pre-made ssh connection
using the following command line:
- ssh -M -S '~'/.ssh/master-user@host:22 [user@]remotehost
+ ssh -M -S '~'/.ssh/master-user@host:22 [user@]remotehost sleep 600
(replace `[user@]remotehost` with your login info). Doing this the
-above script can be run unmodified. After the above command has been
-run on one terminal, enter `chmod +x remote-notmuch.sh` in another
-terminal and then test the script with `./remote-notmuch.sh help`
+above wrapper script can be run unmodified. After the above command has
+been run on **one terminal**, enter `chmod +x remote-notmuch.sh` in
+**another terminal** and then test the script with
+
+ ./remote-notmuch.sh help
-Note that the '~' is inside single quotes for a reason. In this
-case shell never expand it to `$HOME` -- ssh does it by not reading
-`$HOME` but checking the real user home directory from `/etc/passwd`.
-For security purposes this is just how it should be.
+Note that the '~' in the ssh command line above is inside single quotes
+for a reason. In this case shell never expand it to `$HOME` -- ssh does
+it by not reading `$HOME` but checking the real user home directory
+from `/etc/passwd`. For security purposes this is just how it should
+be.
## Tune
See the section *Configure Emacs on the client computer* in
[[remoteusage|remoteusage]] how to do this. The instructions are the same.
+
+
+## Creating master connection
+
+As mentioned so many times, using this solution requires one pre-made
+ssh connection in "master" mode. The simplest way is to dedicate one
+terminal for the connection with shell access to the remote machine:
+
+ ssh -M -S '~'/.ssh/master-user@host:22 [user@]remotehost
+
+One possibility is to have this dedicated terminal in a way that the
+connection has (for example 1 hour) timeout:
+
+ ssh -M -S '~'/.ssh/master-user@host:22 [user@]remotehost sleep 3600
+
+The above holds the terminal. The next alternative puts the command in
+background:
+
+ ssh -f -M -S '~'/.ssh/master-user@host:22 [user@]remotehost sleep 3600
+
+If you don't want this to timeout so soon, use a longer sleep, like 99999999
+(8 9:s, 1157 days, a bit more than 3 years).
+
+A more "exotic" solution would be to make a shell script running on remote
+machine, checking/inotifying when new mail arrives. When mail arrives it
+could send message back to local host, where a graphical client (to be written)
+pops up on display providing info about received mail (and exiting this
+graphical client connection to remote host is terminated).
+
+## Troubleshooting
+
+If you experience strange output when using from emacs first attempt to just
+run
+
+ ./remote-notmuch.sh help
+
+from command line and observe output. If it looks as it should be next uncomment
+the line
+
+ #exec 2>>remote-errors; echo -- >&2; set -x # ... change (no stderr).
+
+in `./remote-notmuch.sh` and attemt to use it from emacs again -- and then
+examine the contents of `remote-errors` in the working directory emacs was
+started. Emacs behaviour may alter slightly as all stderr goes to remote-errors
+now to take that into account when examining results (and if it fixes everything
+then start forwarding stderr to /dev/null...).
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