[SOLVED] Difference between echo of file within double quotes and without double quotes

ankitpandey · 01-10-2013, 11:24 PM

Hello All,

I had a file which i have copied in variable FIL, but when i do echo to FIL variable (without double quotes) it shows the content of file in un-ordered manner and even the other file name present in directory comes as part of content FIL variable whereas when i echo the FIL variable with double quotes it shows the exact content of file in FIL variable.

test is the name of file with say 50 lines

FIL is the variable in which i am storing it temporary.

Code:

FIL=`cat test`

echo $FIL

Above echo of FIL is showing absurd result.

Code:

FIL=`cat test`

echo "$FIL"

Whereas this code is showing correct result. Please explain the difference. How come all the new lines present in temp file are getting eaten and files present in directory also gets include in FIL when echoed without double quotes.

Thanks

pan64 · 01-11-2013, 12:41 AM

you need to check how ' " and ` work in bash. Actually in the first case (echo $FIL) the content of $FIL will be evaluated by the shell during execution. Just try:

Code:

FIL='*'
echo $FIL
echo '$FIL'
echo "$FIL"

see here: http://www.linuxjournal.com/content/bash-quoting, http://wiki.bash-hackers.org/syntax/quoting, http://linuxreviews.org/beginner/Bas...O/en/x303.html, but others may know better links...

theNbomr · 01-11-2013, 09:02 AM

It is a fairly unusual programming pattern to store all of the content of a multi-line text file in a single scalar variable. More often, a variable is used to hold a single line read from a file, or perhaps an array variable holding one line per element. If the file must be processed in some way, it is conventional to read it, usually line-by-line, into a variable in some programming loop structure. If you can explain some of the bigger picture for your intention, perhaps a better solution to you problem can be suggested.

--- rod.