How to read output of sed into a variable

Question

I have variable which has value \"abcd.txt\".

I want to store everything before the \".txt\" in a second variable, replacing the \".t

Answer 1

You can use backticks to assign the output of a command to a variable:

logfile=`echo $a | sed 's/.txt/.log/'`

That's assuming you're using Bash.

Alternatively, for this particular problem Bash has pattern matching constructs itself:

stem=$(textfile%%.txt)
logfile=$(stem).log

or

logfile=$(textfile/%.txt/.log)

The % in the last example will ensure only the last .txt is replaced.