13.- df ::: du
df, information of device name, total blocks, total disk space, used disk space, available disk space and mount points on a file system.
df -h
du, check the information, size of files and directories.
du --help
du - h /mnt/sdcard/AppInventor/assets/logo1.png
du -h /mnt/sdcard/AppInventor/assets/
du -a /mnt/sdcard/AppInventor/assets/
14.- echo
We can use it to write text to a file.
echo “Scooby Doo, Where Are You!” > /mnt/sdcard/my_dog.txt
echo “I’m here!” >> /mnt/sdcard/my_dog.txt
15.- egrep ::: env ::: expand ::: expr ::: ext_logger ::: fallocate ::: false ::: fgrep ::: file ::
egrep, as grep -e (search expression).
env, enviroment variables.
expand, convert tabs into spaces in a file.
fallocate, allocated disk space for a file.
fgrep, as speed grep.
file, information of a file.
16.- find
Search files and directories.
find --help
find /mnt/sdcard/ -name *.txt (Search in all SdCard files *.txt)
find /mnt/sdcard/ -name *.png -o -name *.txt (List of files .png and .txt)
find /system/ -name *.apk (list where is apk files)
find /system/ -name *.apk > /mnt/sdcard/list_my_apk.txt
17.- free
Display the total, free and used amount of physical memory and swap space.
free -h
18.- getprop
Gets an Android system property, or lists them all.
thank you, this is powerful…
is this an update to the existing extension from here?
https://groups.google.com/d/msg/mitappinventortest/zzW_HW7WLXQ/nAAxHktJCwAJ
Taifun
Trying to push the limits! Snippets, Tutorials and Extensions from Pura Vida Apps by 
Taifun.
It is the same extension. This topic is only about its use.
Although in the next few days I will update it to be able to work with the asset files when the application is compiled, as @TIMAI2 proposed in a previous message.
19.- grep
The grep is a filter that is used to search for lines matching a specified pattern and print the matching lines.
https://www.thegeekstuff.com/2009/03/15-practical-unix-grep-command-examples/
grep “seis” /mnt/sdcard/AppInventor/assets/numeros.txt
grep -r “seis” /mnt/sdcard/AppInventor/assets/numeros.txt
grep -v -e “six” /mnt/sdcard/AppInventor/assets/numeros.txt
grep -o -b “seven” /mnt/sdcard/AppInventor/assets/numeros.txt
grep -n “six” /mnt/sdcard/AppInventor/assets/numeros.txt
20.- gunzip ::: gzip
gzip: zip and unzip
gunzip: unzip
gzip --help
gzip -k -c /mnt/sdcard/AppInventor/assets/numeros.txt > /mnt/sdcard/the_numeros.txt.gz
gzip -d -c /mnt/sdcard/the_numeros.txt.gz > /mnt/sdcard/los_numeros.txt
21.- head ::: tail
head -n 3 /mnt/sdcard/numeros.txt (shows the first three lines of the file)
tail -n 2 /mnt/sdcard/numeros.txt (shows the last two lines of the file)
22.- ifconfig ::: ip ::: iw
ifconfig is used in LINUX to show/change network configuration,
but to modify the configuration you need to be root.
ifconfig wlan0 (shows IP)
ip net-tools which is used for performing several network administration tasks.
ip
ip address show wlan0
ip n show
ip neigh show
ip -s neigh
ip -neighbour (to view MAC address of the devices connected to your system.)
iw (similar to ip)
23.- kill ::: killall
kill command sends a signal to a process, if signal is 9 (default) kill a procces.
ps (get PID of process)
kill 19260 (kill MIT Companion)
killall edu.mit.appinventor.aicompanion3 (kill process by name)
24.- ln ::: logcat ::: logname
ln creates hard links by default, or symbolic links with -s ( –symbolic), it is a very important command in LINUX, but I cannot use it with AI2.
logcat -t 300 ( is a command -line tool that dumps a log of system messages)
logname (“name” user, example: u0_a173)
25.- ls
list of files and directories.
https://www.thegeekdiary.com/basic-ls-command-examples-in-linux/
ls -ali /mnt/sdcard/
-a (all, hidden .files)
-l (long format)
-i (show i-node number)
ls -ali /mnt/sdcard/ | grep 4096 (filter with grep lines with number 4096 (size))
ls -ali /mnt/sdcard/DCIM/
ls -ali /mnt/sdcard/DCIM/Camera > /mnt/sdcard/list_my_photos.txt
26.- md5sum
Similar to cksum
md5sum --help
md5sum /mnt/sdcard/numeros.txt
return
74c22f5af060ac90932f7354261d887b numeros.txt
27.- mkdir
Create directory.
mkdir /mnt/sdcard/my_new_directory
mkdir -p /mnt/sdcard/directory/subdirectory/subsubdirectory
29.- mv
mv, move a file or directory, also used to rename a file or directory.
mv /mnt/sdcard/numeros.txt /mnt/sdcard/new_numeros.txt
