Unix scripting

[Kooldino]

Does anyone know how...in either korn, c, or bash, to basically do the equivalent to a RIGHT$ in BASIC?

I need to figure out how to accept an input somehow, then only take the last X characters of it, and store them. Any ideas?

[tutkija]

with perl or php.

on regular expression functions
typically ^ marks beginning and $ end of string.
with ".jpg$" you would seach string ending with .jpg.
I'm not familiar with perl, but some php functions are like ones in perl.

[Ribbit]

I'm sure awk is what you want for this - don't ask me how you do it though (never used awk).

I've got the O'Reilly sed&awk book on my shelf, so I guess if you reeeeeeeally want to know I'll look it up for you...

[spadnos]

Hey - I missed C in that list at first.

You say you want input - from where? User prompt, command line parameter, from a file, from an environment variable, ...

Is the number of characters to keep variable? If so, where is it specified? (same list of possible sources as the input string)

Where do you want the result saved? (file, environment, printed to stdout, etc.)

I know perl can do this (though I don't know perl)
Awk can do it - you need something like print substr($0, length-X, X) as the guts of the awk script
It's trivial in C, other than all the stuff you need for checking parameters or reading environment variables.

It's probably doable in a shell script as well

Note that any language that you can take the left X characters can also probably give you the right X (reverse string, take first X characters, reverse the result)

- Steve

[Ribbit]

Erm, by "C" I think he meant the C-shell...

[spadnos]

Yeah, you're right.
(I'm a bonehead )

- Steve

[spadnos]

OK. From the command line, you can extract the rightmost X characters with the following:

awk '{print substr( $0, length($0)-(X-1), X ) }'

You will need some variation on that theme depending on where the input comes from, and where it's going:

awk '{print substr( $0, length($0)-9, 10 ) }' listfile > rightside

will take the rightmost 10 characters of every line in the file listfile, and output them into the file rightside (one output line per input line).

 echo $PWD | awk '{print substr( $0, length($0)-9, 10 ) }'

will print the rightmost 10 characters of the current directory.
...
modify at will for the desired effect.

- Steve

[Kooldino]

I did indeed mean c shell, sorry I wasn't clearer.

spadnos - That should do nicely. Thanks!