Project: a terminal dashboard

You are going to write a script that prints a small dashboard when you open Termux. It shows the date and how long the phone has been up. It shows disk and memory use, and battery if the device reports it. It counts your installed packages, then adds a local line that works with no network at all.

What you'll be able to do

• Lay out aligned text with echo and printf.
• Feed one command's output into another with command substitution.
• Read disk and memory figures from df and free.
• Detect whether a file exists before reading it, so the script copes with a phone that has no battery sensor.
• Branch on a flag with a case statement.

What you are building

A script called dash.sh that prints a fixed set of sections, each separated by a rule. Run it plain for the full dashboard, or pass --brief for a shorter one.

$ sh dash.sh
Termux dashboard
Saturday 24 October 2026
uptime:3 days
----------------------------------
Disk
  18G used of 51G (37%)

Step 1: The header

Start with a title, the full date, and the uptime. The raw uptime line has extra words. Trim it with sed to the part after up and before the first comma.

$ echo "$(date '+%A %d %B %Y')"
Saturday 24 October 2026
$ echo "uptime:$(uptime | sed 's/.*up //; s/,.*//')"
uptime:3 days

The format string %A %d %B %Y gives the weekday, day, month name, and year. Everything inside $(...) runs first, and its output drops into the surrounding string.

Step 2: Disk usage

df -h lists the filesystems with human-readable sizes. tail -n +2 drops the header line. awk then picks out the used size, the total, and the percentage.

$ df -h / | tail -n +2 | awk '{printf "  %s used of %s (%s)\n", $3, $2, $5}'
  18G used of 51G (37%)

Step 3: Memory

free -h prints a memory table with a header row and a Mem: row. Match the Mem: row and print the used and total columns. If free is missing on your install, add it with pkg install procps.

$ free -h | awk '/^Mem:/ {printf "  %s used of %s\n", $3, $2}'
  2.1G used of 5.8G

Step 4: Battery, if it exists

Not every phone exposes a battery to Termux. The capacity is a plain number in a file under the power supply tree. Test that the file is readable first.

BAT=/sys/class/power_supply/BAT0/capacity
if [ -r "$BAT" ]; then
  echo "  $(cat "$BAT")%"
else
  echo "  not available"
fi

Step 5: Count the installed packages

The count differs between a Debian-style system and Termux, so check which tool is present with command -v. dpkg-query lists every package name with no spacing. wc -c counts the characters, which equals the number of packages. On Termux, pkg list-installed prints one line per package. wc -l counts them.

$ if command -v dpkg-query >/dev/null 2>&1; then dpkg-query -f '.' -W | wc -c | tr -d ' '; else pkg list-installed | wc -l | tr -d ' '; fi
312

Step 6: The offline local line

The last section replaces a weather line with something that always works: the time zone and the current time, both from date. No network is involved, so the dashboard never hangs waiting for a reply.

$ echo "  timezone $(date +%Z)"; echo "  now      $(date '+%H:%M')"
  timezone IST
  now      21:40

Step 7: The --brief flag and the finished script

Put the sections into functions, then choose which to print with a case statement. case compares a value against several patterns and runs the block for the first match. The empty pattern "" matches no argument at all, and * catches anything else.

#!/bin/sh
# dash.sh: a compact terminal dashboard. Usage: sh dash.sh [--brief]

BRIEF=0
case "$1" in
  --brief) BRIEF=1 ;;
  "")      BRIEF=0 ;;
  *)       echo "usage: dash.sh [--brief]" >&2; exit 2 ;;
esac

rule() { echo "----------------------------------"; }
show_disk() {
  echo "Disk"
  df -h / | tail -n +2 | awk '{printf "  %s used of %s (%s)\n", $3, $2, $5}'
}
show_memory() {
  echo "Memory"
  free -h | awk '/^Mem:/ {printf "  %s used of %s\n", $3, $2}'
}
show_battery() {
  BAT=/sys/class/power_supply/BAT0/capacity
  if [ -r "$BAT" ]; then
    echo "Battery"; echo "  $(cat "$BAT")%"
  else
    echo "Battery"; echo "  not available"
  fi
}
show_packages() {
  echo "Packages"
  if command -v dpkg-query >/dev/null 2>&1; then
    echo "  $(dpkg-query -f '.' -W | wc -c | tr -d ' ') installed"
  elif command -v pkg >/dev/null 2>&1; then
    echo "  $(pkg list-installed | wc -l | tr -d ' ') installed"
  else
    echo "  unknown"
  fi
}
show_local() {
  echo "Local"
  echo "  timezone $(date +%Z)"
  echo "  now      $(date '+%H:%M')"
}

echo "Termux dashboard"
echo "$(date '+%A %d %B %Y')"
echo "uptime:$(uptime | sed 's/.*up //; s/,.*//')"
rule
if [ "$BRIEF" -eq 1 ]; then
  show_disk; show_memory; show_local
else
  show_disk; rule; show_memory; rule; show_battery; rule; show_packages; rule; show_local
fi

Run it plain for the full dashboard.

$ sh dash.sh
Termux dashboard
Saturday 24 October 2026
uptime:3 days
----------------------------------
Disk
  18G used of 51G (37%)
----------------------------------
Memory
  2.1G used of 5.8G
----------------------------------
Battery
  76%
----------------------------------
Packages
  312 installed
----------------------------------
Local
  timezone IST
  now      21:40

An unknown flag falls through to the * pattern and exits with status 2.

$ sh dash.sh --wat; echo "exit=$?"
usage: dash.sh [--brief]
exit=2

Quick reference

Command or syntax	What it does
date '+%A %d %B %Y'	Prints the weekday, day, month name, and year.
date +%Z	Prints the time zone abbreviation.
df -h /	Lists the root filesystem with human-readable sizes.
free -h	Prints the memory table with human-readable sizes.
printf "fmt" a b	Prints fmt with %s replaced by each argument.
[ -r file ]	True when the file exists and is readable.
command -v name	Prints the path of a command, or nothing if absent.
case "$1" in ... esac	Runs the block matching the first pattern.

Where to take it next

• Add a --watch mode that redraws the dashboard every few seconds with a while loop and sleep, clearing the screen with clear between passes.
• Colour the disk and memory lines with tput when the percentage passes a threshold, so a nearly full phone stands out.

Read Shell scripting basics for the $(...) pattern, functions and case.