Get Application Name/ Label via ADB Shell or Terminal

adb shell pm list packages will give you a list of all installed package names.

You can then use dumpsys | grep -A18 "Package \[my.package\]" to grab the package information such as version identifiers etc

just enter the following command on command prompt after launching the app:

adb shell dumpsys window windows | find "mCurrentFocus"

if executing the command on linux terminal replace find by grep

If you know the app id of the package (like org.mozilla.firefox), it is easy. First to get the path of actual package file of the appId,

$  adb shell pm list packages -f com.google.android.apps.inbox
package:/data/app/com.google.android.apps.inbox-1/base.apk=com.google.android.apps.inbox

Now you can do some grep|sed magic to extract the path : /data/app/com.google.android.apps.inbox-1/base.apk

After that aapt tool comes in handy :

$  adb shell aapt dump badging /data/app/com.google.android.apps.inbox-1/base.apk
...
application-label:'Inbox'
application-label-hi:'Inbox'
application-label-ru:'Inbox'
...

Again some grep magic to get the Label.

A shell script to accomplish this:

#!/bin/bash

# Remove whitespace
function remWS {
    if [ -z "${1}" ]; then
        cat | tr -d '[:space:]'
    else
        echo "${1}" | tr -d '[:space:]'
    fi
}

for pkg in $(adb shell pm list packages -3 | cut -d':' -f2); do
    apk_loc="$(adb shell pm path $(remWS $pkg) | cut -d':' -f2 | remWS)"
    apk_name="$(adb shell aapt dump badging $apk_loc | pcregrep -o1 $'application-label:\'(.+)\'' | remWS)"
    apk_info="$(adb shell aapt dump badging $apk_loc | pcregrep -o1 '\b(package: .+)')"

    echo "$apk_name v$(echo $apk_info | pcregrep -io1 -e $'\\bversionName=\'(.+?)\'')"
done