Thursday, April 28, 2022

[SOLVED] sed - conditional replacement of similar string patterns

Issue

I try to replace/append strings in text files with sed. Another string ("green") needs to be matched before a replacement is allowed.

The strings are very similar:

apple >> apple_tree
apple X1 >> apple_tree
appleX1 >> apple_tree

This code works if the condition is not taken into account and the first occurrence of one of the strings should be replaced:

find . -type f -exec sed -i '0,/apple|apple X1|appleX1/{s/apple|apple X1|appleX1/apple_tree/}' {} +

This code can not be executed (prompt is waiting)

find . -type f -exec sed -i '/green/,// /apple|apple A0|appleA0/{s/apple|apple A0|appleA0/apple_tree/}' {} +

Although this one works without alternative patterns:

find . -type f -exec sed -i '/green/,// s/apple/apple_tree/' {} +

Unfortunately, using word border indicators like \<apple\> does not work either.

The OS is Ubuntu 20.04. The solution is not restricted to sed.

Thank you.

Edit:

Input:

orange
pear
kiwi
apple X1
mango
banana
apple

green

orange
pear
kiwi
apple X1
mango
appleX1
banana
apple

Code execution

Desired output:

orange
pear
kiwi
apple X1
mango
banana
apple

green

orange
pear
kiwi
apple_tree
mango
apple_tree
banana
apple_tree

Solution

You seem to want:

sed -i -e '/green/,$s/apple\( A0\|A0\|\)/apple_tree/'

Check out https://www.gnu.org/software/sed/manual/sed.html https://www.grymoire.com/Unix/Sed.html https://regexcrossword.com/



Answered By - KamilCuk
Answer Checked By - Terry (WPSolving Volunteer)
at