Would like to write a bash script that replaces some strings in a text file, however I am getting hung up on how to replace the contents inside a 'value' for a variable.
Suppose the value I wish to set inside a text file could be :
TCP_IN = "123,35,995"
.. where 123,35,995 could be any string (not just numbers with commas.
How could I replace this keypair searching for TCP_IN = "*" and set the value inside where * is, from within a bash script ?
You can use
sed -E 's/(TCP_IN *= *")[^"]+/\1MyNewVal/g'
See the IDEONE demo
The regex matches and captures into Group 1 TCP_IN followed with zero or more spaces, followed with a = symbol, followed with again zero or more spaces, and then [^"]+ matches 1 or more characters other than a " ([^...] is a *negated character class that matches all characters but those defined inside the char class).
MyNewVal, you can do it as follows : sed -E 's/(TCP_IN *= *")[^"]+/\1'$MyNewVal'/g'' in them ? The syntax works > ideone.com/0j1VDt . Only once, not when run consecutively. :)