MobileRead Forums - View Single Post - Shell script to wait for user input from K3g keyboard

knc1 · 03-28-2012, 03:37 PM

One hint of something to check for in __any__ shell script -
The handling of whitespace.
More correctly, the handling of the "Input Field Seperator" character(s).

Often defined in the "IFS" variable and having the default of "space, tab, new-line" characters.

I can read where G.M. has dealt with space and new-line.
Perhaps tab (\x09) needs to be dealt with also?

Since this code is a shell function, and since most shell implementations recognize a function local setting of IFS -
Perhaps adding the pair of lines:

local IFS
IFS='some character you know will never show up in the key codes'

Will aid in dealing with the whitespace issues.

One hint about re-using G.M.'s function -

It is a function.
Add your code outside to the function and call the function from your added code passing the two expected parameters.

If running this function under Bash or Bash's sh mode -
You can pass any character (except \x00) by escaping it in the call.
I.E:
getkb $(printf '%q %q', parm-1, parm-2)
That will properly escape the two parameters at the point of the call and Bash's function argument processing will un-escape them.

For other sh implementations - a bit of experimenting might be required.

03-28-2012, 03:37 PM	#21
knc1 Going Viral Posts: 17,212 Karma: 18210809 Join Date: Feb 2012 Location: Central Texas Device: No K1, PW2, KV, KOA	One hint of something to check for in __any__ shell script - The handling of whitespace. More correctly, the handling of the "Input Field Seperator" character(s). Often defined in the "IFS" variable and having the default of "space, tab, new-line" characters. I can read where G.M. has dealt with space and new-line. Perhaps tab (\x09) needs to be dealt with also? Since this code is a shell function, and since most shell implementations recognize a function local setting of IFS - Perhaps adding the pair of lines: local IFS IFS='some character you know will never show up in the key codes' Will aid in dealing with the whitespace issues. One hint about re-using G.M.'s function - It is a function. Add your code outside to the function and call the function from your added code passing the two expected parameters. If running this function under Bash or Bash's sh mode - You can pass any character (except \x00) by escaping it in the call. I.E: getkb $(printf '%q %q', parm-1, parm-2) That will properly escape the two parameters at the point of the call and Bash's function argument processing will un-escape them. For other sh implementations - a bit of experimenting might be required.