SED - Insert saved value after certain pattern when a specific string doesn't exist in the file

Question

I have files that look similar to this :

LET: DimX   (2660.0)
LET: DimZ   (1050.0)
LET: DimS   (0.8)
LET: DREHEN (20)

DIM: X DimX
     Z DimZ+0.5
     S DimS
     

REF: X1 FOD-23.24
     X2 FOD-23.24
     Z1 FOD-24.86
     Z2 FOD-24.86

POS: CENT_FUNC 1
     QSU 10 QSD 10
     TURN_AROUND

And like this - note the STAINLESS in the 2nd one:

LET: DimX   (2660.0)
LET: DimZ   (1050.0)
LET: DimS   (0.7)
LET: DREHEN (20)

DIM: X DimX
     Z DimZ+0.5
     S DimS
     STAINLESS

REF: X1 FOD-23.24
     X2 FOD-23.24
     Z1 FOD-24.86
     Z2 FOD-24.86

POS: CENT_FUNC 1
     QSU 10 QSD 10
     TURN_AROUND

I want to save the value in Brackets in the line matching LET: DimS ( XX ) and insert a new line MAT: 'XX correction ' - where XX is the save value. after S DimS

• But only if the file whole doesn't contain the string STAINLESS.

So this should be the outcome for the 1st example :

LET: DimX   (2660.0)
LET: DimZ   (1050.0)
LET: DimS   (0.8)
LET: DREHEN (20)

DIM: X DimX
     Z DimZ+0.5
     S DimS
     MAT: '0.8 correction'


REF: X1 FOD-23.24
     X2 FOD-23.24
     Z1 FOD-24.86
     Z2 FOD-24.86

POS: CENT_FUNC 1
     QSU 10 QSD 10
     TURN_AROUND

Outcome of the 2nd example should stay as it was as it contains STAINLESS:

LET: DimX   (2660.0)
LET: DimZ   (1050.0)
LET: DimS   (0.7)
LET: DREHEN (20)

DIM: X DimX
     Z DimZ+0.5
     S DimS
     STAINLESS

REF: X1 FOD-23.24
     X2 FOD-23.24
     Z1 FOD-24.86
     Z2 FOD-24.86

POS: CENT_FUNC 1
     QSU 10 QSD 10
     TURN_AROUND

I've tried this to add the line after S DimS pattern:

sed -i -E '/S DimS/I a  \\t MAT: "'"0.8 correction"'"'

But that just gives me:

LET: DimX   (2660.0)
LET: DimZ   (1050.0)
LET: DimS   (0.8)
LET: DREHEN (20)

DIM: X DimX
     Z DimZ+0.5
     S DimS
     MAT: "0.8 correction"

REF: X1 FOD-23.24
     X2 FOD-23.24
     Z1 FOD-24.86
     Z2 FOD-24.86

POS: CENT_FUNC 1
     QSU 10 QSD 10
     TURN_AROUND

And:

    LET: DimX   (2660.0)
LET: DimZ   (1050.0)
LET: DimS   (0.7)
LET: DREHEN (20)

DIM: X DimX
     Z DimZ+0.5
     S DimS
     MAT: "0.8 correction"
     STAINLESS

REF: X1 FOD-23.24
     X2 FOD-23.24
     Z1 FOD-24.86
     Z2 FOD-24.86

POS: CENT_FUNC 1
     QSU 10 QSD 10
     TURN_AROUND

And obvioulsy won't save the value in the brackets...

Can anyone help me please?

Thank you.

Answer 1

If you're amenable to an awk solution, which is often easier than sed when there's logic to perform beyond simple string manipulation ...

# Capture the correction amount
/LET: DimS/ { correction = $3; gsub(/[()]/, "", correction) }

# Get ready to print
$1 == "DIM:" { f = 1 }

# Abort print!!
$1 == "STAINLESS" { f = 0 }

# Now is the time to print the extra line if the flag is still set
NF == 0 && f { printf "     MAT: '%s correction'\n", correction; f = 0 }

# Output the original lines of the file
{ print }

Test first example:

$ awk -f a.awk file
LET: DimX   (2660.0)
LET: DimZ   (1050.0)
LET: DimS   (0.8)
LET: DREHEN (20)

DIM: X DimX
     Z DimZ+0.5
     S DimS
     MAT: '0.8 correction'


REF: X1 FOD-23.24
     X2 FOD-23.24
     Z1 FOD-24.86
     Z2 FOD-24.86

POS: CENT_FUNC 1
     QSU 10 QSD 10
     TURN_AROUND

Try it with your second "STAINLESS" example and you'll see that the extra line is not printed.

Answer 2

This might work for you (GNU sed):

sed -E ':a;N;$!ba;/STAINLESS/b;
    s/^(.*LET:\sDimS\s*\(([^)]*).*\n(\s*)S DimS[^\n]*\n)/\1\3MAT: '\''\2 correction'\''/' file

Gather up the entire file into memory and test it to see if it contains the word STAINLESS . If so, bail out otherwise: using pattern matching insert the required text.