Korn shell - some nuggets

Archive - Originally posted on "The Horse's Mouth" - 2008-05-30 08:31:11 - Graham Ellis
I've presented some Korn Shell Training over the last couple of days ,,, and I cut and pasted a few snippets which I thought might be of interest.

• Korn Shell - looping through a series of outputs from a command

$ for file in `ls`; do

> echo $file

> done

LinuxBasicsAdmin.book.pdf

Sefas.book.pdf

dat_backup

dat_backup2

dat_backup3

filestat

funky

gvar

hello_korn

kornserver.cgi

ksh.book.pdf

ksh.ps

numtee

pippa

script_korn

selk

sharon

stroppy

townline

tracey

$

• Korn shell - integer (counting) loop

$ for (( kay=0 ; $kay<10 ; kay=$kay+1 )) ; do

> echo $kay

> done;

0

1

2

3

4

5

6

7

8

9

$

• there are a lot of clever modifiers in the Korn shell you can use on variables such as these which will let you look at part of a string.

$ stwing="jhkasdhjkasdhjkadshjkasdtqwetyuqwe678678sdhjksdhjkasd"

$ print ${stwing:40}

sdhjksdhjkasd 

$ print ${stwing:40:5}

sdhjk

$

• using read to read from stdin in ksh, including a prompt.

$ read treacle?pie

pieCustard

$ echo $treacle

Custard

$

• capturing STDERR into a variable in the Korn Shell

$ tryme=`mkdir 2008-05-29 2>&1`

$ echo $tryme

mkdir: cannot create directory `2008-05-29': File exists

$

• branching on the status returned by a command in the Korn Shell

if mkdir 2008-05-29

then

 echo yay

else

 echo nay

fi

See also Korn Shell Training and Korn Shell Resource Index.

Look back at the previous entries on this blog so see examples of environment settings in the Korn Shell, and also how variables may be used for Strings, Integers and as arrays.

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Korn shell - some nuggets