Add system-info Linux systemd user unit

Update the `system-info` directory with the addition of a `systemd`
service file and an new Linux script to display current CPU temperature
and core/thread utilization. Update `.conduit.yaml` with addition
`apt` dependencies `sysstat` and `jq`. Update the install and remove
scripts to setup and tear down the `systemd` user unit. Lastly, decrease
the `tmux` status line update interval from 5 to 2 seconds.

.conduit.yaml

@@ -4,6 +4,8 @@
     - tmux
     - xclip
     - urlview
+    - sysstat
+    - jq
 - brew:
     - tmux
     - urlview

system-info/install.sh

@@ -5,4 +5,8 @@ script_dir=`dirname $0`
 if [ `uname` = Darwin ]; then
   cp $script_dir/system-info.plist ~/Library/LaunchAgents/system-info.plist
   launchctl load -w ~/Library/LaunchAgents/system-info.plist
+else
+  cp $script_dir/system-info.service ~/.config/systemd/user/system-info.service
+  systemctl --user enable system-info
+  systemctl --user start system-info
 fi

system-info/remove.sh

@@ -3,4 +3,7 @@
 if [ `uname` = Darwin ]; then
   launchctl unload ~/Library/LaunchAgents/system-info.plist
   rm ~/Library/LaunchAgents/system-info.plist
+else
+  systemctl --user stop system-info
+  systemctl --user disable system-info
 fi

system-info/system-info-Linux.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+
+cache_dir=~/.cache/tmux
+cache_file=$cache_dir/system-info
+
+# Make sure the output directory exists.
+if [ ! -d $cache_dir ]; then
+  mkdir -p $cache_dir
+fi
+
+# Cleanup cache file when interrupted.
+trap '[ -f $cache_file ] && rm $cache_file; exit' INT
+trap '[ -f $cache_file ] && rm $cache_file; exit' TERM
+
+while true; do
+  # Parse the current CPU load on all cores/threads.
+  cpu_load=`mpstat -P ALL -n 1 -u 1 -o JSON | \
+    jq '.sysstat.hosts[0].statistics[0]["cpu-load"][1:]|.[].idle' | \
+    awk '$idle ~ /[-.0-9]*/ { printf "%s", substr("█▇▆▅▄▃▂▁ ", int($idle / 11), 1) }'`
+  # Parse the current CPU package temperature.
+  cpu_temp=`sensors coretemp-isa-0000 | awk 'NR == 3 { print substr($4, 2) }'`
+  # Write to the cache file.
+  echo "$cpu_temp $cpu_load" > $cache_file
+done

system-info/system-info.service

@@ -0,0 +1,8 @@
+[Unit]
+Description=System Info
+
+[Service]
+ExecStart=/home/benie/.config/tmux/system-info/system-info-Linux.sh
+
+[Install]
+WantedBy=default.target

tmux.conf

@@ -19,7 +19,7 @@ set -g history-limit 1000000
 set -g display-time 4000
 
 # Refresh 'status-left' and 'status-right' more often
-set -g status-interval 5
+set -g status-interval 2
 
 # Upgrade $TERM
 set -g default-terminal "tmux-256color"