From 0f1ee5f53323317cfbd449235f2f185d64684207 Mon Sep 17 00:00:00 2001
From: Erik Arvstedt <erik.arvstedt@gmail.com>
Date: Sun, 17 May 2020 23:46:44 +0200
Subject: [PATCH] examples: improve shell session usability

- Add usage prompt when starting shell sessions

- Give all examples an uniform interface ("c") for running commands
  or starting a shell on the node.
---
 examples/deploy-container.sh   |  8 +++++++-
 examples/deploy-nixops.sh      |  1 +
 examples/start-bash-session.sh | 13 +++++++++++--
 3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/examples/deploy-container.sh b/examples/deploy-container.sh
index d48dfb4..f9fc494 100755
--- a/examples/deploy-container.sh
+++ b/examples/deploy-container.sh
@@ -62,7 +62,13 @@ in {
 }
 EOF
 # Run command in container
-c() { sudo extra-container run demo-node -- "$@" | cat; }
+c() {
+    if [[ $# > 0 ]]; then
+        sudo extra-container run demo-node -- "$@" | cat;
+    else
+        sudo nixos-container root-login demo-node
+    fi
+}
 
 echo
 echo "Bitcoind service:"
diff --git a/examples/deploy-nixops.sh b/examples/deploy-nixops.sh
index d7209e8..155cc5e 100755
--- a/examples/deploy-nixops.sh
+++ b/examples/deploy-nixops.sh
@@ -38,6 +38,7 @@ nixops deploy -d bitcoin-node
 # Connect to node
 nixops ssh bitcoin-node systemctl status bitcoind
 
+c() { nixops ssh bitcoin-node "$@"; }
 # Uncomment to start a shell session here
 # . start-bash-session.sh
 
diff --git a/examples/start-bash-session.sh b/examples/start-bash-session.sh
index 6ed16bf..37ba4fc 100644
--- a/examples/start-bash-session.sh
+++ b/examples/start-bash-session.sh
@@ -1,6 +1,15 @@
 # Start an interactive bash session in the current bash environment.
 
+USAGE_INFO='
+Starting shell...
+Run "c COMMAND" to execute a command on the bitcoin node
+Run "c" to start a shell session inside the node'
+
 # BASH_ENVIRONMENT contains definitions of read-only variables like 'BASHOPTS' that
-# cause warnings on importing. Suppress these warnings during bash startup.
+# cause warnings on evaluation. Suppress these warnings while sourcing.
 BASH_ENVIRONMENT=<(declare -p; declare -pf) \
-  bash --rcfile <(echo 'source $BASH_ENVIRONMENT 2>/dev/null')
+USAGE_INFO="$USAGE_INFO" \
+  bash --rcfile <(echo '
+    source $BASH_ENVIRONMENT 2>/dev/null
+    echo "$USAGE_INFO"
+  ')