problem to use an alias in the ksh functions

[alexvai]

Hi,
I have problem to use an alias that defined in ksh93 script, in the
functions in the same script onm Linux.

I definied an alias in main:
alias echo='echo -e'
in order that echo will read backslashes


but when i executed it in function, the alias didnt work, and
performewd a regular echo, without -e


------------------------
cat test.ksh


#!/bin/ksh


alias echo='echo -e'


checkUsage


checkUsage()
{
echo "\ntest\n"



}


---------------------


> ./test.ksh


\nTest\n

[drl]

Hi.

The code you posted will not run in most Bourne-like shells that I know of because you call a function before you define it:

% ./user1
./user1[5]: checkUsage: not found [No such file or directory]

Assuming we correct that, then I get for script "s1":

#!/usr/bin/env ksh

# @(#) s1	Demonstrate ksh alias.

# Utility functions: print-as-echo, print-line-with-visual-space, debug.
pe() { for i;do printf "%s" "$i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }
db() { ( printf " db, ";for i;do printf "%s" "$i";done; printf "\n" ) >&2 ; }
db() { : ; }
C=$HOME/bin/context && [ -f $C ] && . $C

pe
set -vx
alias echo='echo -e'

checkUsage()
{
echo "\ntest\n inside  calling function"
} 

checkUsage

echo "\ntest\n outside calling function"

printf "\ntest\n outside calling function (printf)\n"

echo '\ntest\n outside calling function'

producing:

% ./s1

Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
OS, ker|rel, machine: Linux, 2.6.26-2-amd64, x86_64
Distribution        : Debian GNU/Linux 5.0.7 (lenny) 
ksh 93s+

alias echo='echo -e'

+ alias echo='echo -e'
checkUsage()
{
echo "\ntest\n inside  calling function"
} 

checkUsage

+ checkUsage
+ echo -e '\ntest\n inside  calling function'

test
 inside  calling function
echo "\ntest\n outside calling function"

+ echo -e '\ntest\n outside calling function'

test
 outside calling function
printf "\ntest\n outside calling function (printf)\n"


test
 outside calling function (printf)
+ printf '\ntest\n outside calling function (printf)\n'
echo '\ntest\n outside calling function'
+ echo -e '\ntest\n outside calling function'

test
 outside calling function

This seems to work for me.

It shows some of the variations that could be tried. The code that sets "-vx" is often useful to see details of what the shell is doing, which is not always what you think it does. It can be more difficult to read the results, however, because the output caused by "-vx" is written to stderr, and may or may not appear where you expect it with the other output -- you'll get it, but the order can be confusing.

Note that you will often see advice to use functions instead of aliases, and to use printf instead of echo. See the function definitions in the script for "pe", a replacement for echo that I use.

Best wishes ... cheers, drl