sh script writing help

[Matthew Seaman]

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On 30/05/2010 07:58:58, Aiza wrote:
> Anh Ky Huynh wrote:
>> On Sun, 30 May 2010 14:10:36 +0800
>> Aiza <aiza21 at comclark.com> wrote:
>>
>>> Dan Nelson wrote:
>>>> In the last episode (May 30), Aiza said:
>>>>> In a .sh type script I have && exerr " very long message gt 250
>>>>> char" all on the same line. This is a real pain to edit.
>>>>>
>>>>> Is there some code a can use to continue this on the next line
>>>>> so I can see it on the screen and still have the command
>>>>> function? I tried \ with no luck.
>>>> \ should work just fine:
>>>>
>>>> $ echo "long line \
>>>> split onto two"
>>>> long line split onto two
>>>> $
>>>>
>>>
>>> You example works only because the continuation starts at position
>>> 1.
>>>
>>> $   [ -n "${test-name-fowarding}" -o -n "${test-noname}" ] || \
>>>      exerr "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\
>>>             xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
>>> this is for ease of reading the code but will display with a bunch
>>> of spaces in the middle of the sentence. The \ works fine bypassing
>>> all white space between code not so for white space between the "
>>> ".
>>>
>>> Is there a coding method to get around this?
>>
>> Do you try to read your expression from a file?
>>     exerr `cat /path/to/data`
>>
>> the contents of /path/to/data are your very long string.

A standard means of doing this sort of thing is to use a 'Here' document:

if ! [ -n "${test-name-forwarding}" -o -n "${test-noname}" ]; then
    exerr <<-E_O_EXERR
	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
E_O_EXER
fi

The '<<-' operator is a variant on the usual '<<' operator used for
this: the only difference is that it strips leading tabs from the lines
in the here document.

	Cheers,

	Matthew

- -- 
Dr Matthew J Seaman MA, D.Phil.                   7 Priory Courtyard
                                                  Flat 3
PGP: http://www.infracaninophile.co.uk/pgpkey     Ramsgate
JID: matthew at infracaninophile.co.uk               Kent, CT11 9PW
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