Sometime ago I said I was going to attempt an Android project.
I got my phone for XMAS and after installing a terminal program I realised how limited the command line is.
I do NOT intend to __root__ the phone at this point but I can read and write to certain folders.
The biggest problem is the vast majority of the commands are missing - OUCH!
awk, printf, sed, hexdump, xxd, od, and many many others we take for granted are not available...
I DO have a subset of builtins of which echo -n -e -E is but one.
The terminal program has a large subset of the terminal escape codes so this is a bonus.
This set me on a quest to start my own commands using what I have got to play with.
This DEMO hex dumper for example is a starter.
This is as bizarre as shell scripting can possibly get.
It is SSLLOOWW but gives me the ability to read in small amounts of binary data for ideas in my head.
I have no idea yet whether this works on my phone but I will let you all know in due course.
The phones's default shell [sh] is bash...
** My question is can this be speeded up as it takes around a minute or so to read a random 256 byte file on this MBP. **
This DEMO works like this:-
1) 256 single byte files are generated from 0x00 to 0xFF named as 00.HEX to FF.HEX.
2) $1 is the full path and filename required for viewing.
3) The file $1 is read byte by byte and compared against the single byte files cat(ted) using a brute force method.
4) With the exception of two values, NULL and NEWLINE, these binary values are are printed onto STDOUT only for this DEMO.
5) Read the code for NULL and NEWLINE.
6) The HEX values are extracted from the filenames, NOT, the bytes themselves... <wink>
This was the only way I could think of to get binary into my machine with a small subset of the shell command available...
There is nothing on the net about this... ;o/
LBNL the first display is a random file generated to show it works in binary mode and the second is a hexdump of itself.
Note that hexdump is there for comparison only...
Code:
#!/bin/bash
# hex.sh </full/path/to/filename>
ifs_str="$IFS"
IFS=""
for high_nibble in 0 1 2 3 4 5 6 7 8 9 A B C D E F
do
for low_nibble in 0 1 2 3 4 5 6 7 8 9 A B C D E F
do
echo -e -n "\x$high_nibble$low_nibble" > /tmp/$high_nibble$low_nibble'.HEX'
done
done
listing=$(ls /tmp/*.HEX)
count=0
char=""
hexval="/tmp/00.HEX"
subscript=0
chr=""
hexdump -C $1
while read -s -d '' -r -n 1 char
do
subscript=0
count=0
while [ $count -le 255 ]
do
hexval="${listing:$subscript:${#hexval}}"
chr=$(cat $hexval)
if [ "$char" == "$chr" ]
then
if [ "$chr" == "" ]
then
echo -n "00 "
break
fi
if [ "$chr" != "" ]
then
echo -n "${hexval:$((${#hexval}-6)):2} "
break
fi
fi
subscript=$((subscript+${#hexval}+1))
count=$((count+1))
if [ $count -eq 256 ]
then
echo -n "0A "
fi
done
done < $1
IFS="$ifs_str"
exit
Results, edited to __remove__ the ultra long string created:-
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