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Shell Programming and Scripting

Directing cat or grep command in variable

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# 1  
Old 03-11-2013
Directing cat or grep command in variable
Hi,

I still have the problem with directing information from cat or grep to a variable.

For instance:
Code:
XMSG "$(date +%Y_%m_%d)_error_report.txt" "$(cat "$(date +%Y_%m_%d)_error_report.txt")" &

Works! The text received by cat is directed to my function.

If it is written like this, my variable var is empty
Code:
var=$(cat "$(date +%Y_%m_%d)_error_report.txt")

Same effect here:
Code:
var=$(grep "sdhdjhf" text.txt)

Can anybody please explain why the redirection does not work?
# 2  
Old 03-11-2013
I would doubt on the multiple lines that cat file and grep something file would return Smilie

Or non-existence of the file in case of cat and nothing found in case of grep
# 3  
Old 03-11-2013
It oughta work. Seems to work here with this test scenario. Similar to previous response, two likely causes would be "file is empty" or "grep didn't find anything".

Code:
$cat temp.sh
echo "Line 1"  > lines.x
echo "Line 2" >> lines.x
x=`cat lines.x`
echo x = $x
y=$(cat lines.x)
echo y = $y
rm lines.x

$./temp.sh
x = Line 1 Line 2
y = Line 1 Line 2

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