CODEWITHSUNDEEP
bashshell
user3137879
user3137879

Reputation: 63

reading a string from file

I want to read a string from file and print it as follow : 

LINE=tr '\n' ' ' < $FILENAME
x1=$LINE
echo $LINE

but the command echo $LINE display an empty line ?

Upvotes: 0

Views: 90

Answers (3)

Ruud Helderman
Ruud Helderman

Reputation: 11018

As already pointed out by the other posters, to embed the output of the tr command into another command (in this case LINE=...), surround the tr command by $(...). In bash this is known as command substitution.

LINE=$(tr '\n' ' ' < "$FILENAME")

In case you intend to use $LINE as a sequence of parameters for subsequent commands (in this case echo), then newlines are eventually replaced by space during word splitting. This would make tr superfluous; you might as well do this:

LINE=$(cat "$FILENAME")

or even better:

LINE=$(< "$FILENAME")

Word splitting is not effective inside double quotes; so echo "$LINE" would still require tr to remove newlines.

Upvotes: 2

anubhava
anubhava

Reputation: 785126

You should be using command substitution like this:

LINE=$(tr '\n' ' ' < "$FILENAME")

But this will store tr's output into LINE variable.

Upvotes: 2

jcarballo
jcarballo

Reputation: 29103

I think you need to put the call to the tr command with backquotes:

LINE=`tr '\n' ' ' < $FILENAME`

Upvotes: 1

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