[SOLVED] using BASH how can i replace all text between two patterns containing forward slashes?

Issue

I'm trying to write a script that replaces text in a text file between two patterns "opt/" and "/". An example of the data in the file is:

daw9udiwa9diuoawdj098awd89a0909w  opt/TEXTTOREPLACE/app-data/version.txt
wdalkwhjf8aufwaoif98fawfojaw98f8  opt/TEXTTOREPLACE/app-data/package.txt
awdhaw9d8yawdf8uaw9f8uwafhiuhawf  opt/TEXTTOREPLACE/bin/somefile/somefile
wdalkwhjf8aufwaoif98fawfojaw98f8  opt/TEXTTOREPLACE/bin/someapp/somefile

I've looked at using the 'sed' command, but the pattern matching is confusing me.

I have tried:

sed -e 's!\/[^\/]*\/!\/CHANGE TO ME\/!' 

This works - but I would like to add in the "opt" at the beginning to minimise errors

So I tried the following with no luck

sed -e 's!opt\/[^opt\/]*\/!opt\/CHANGE TO ME\/!'

I will be using a $VAR to replace text so for example

VAR=CHANGED
sed -e 's!opt\/[^opt\/]*\/!opt\/$VAR\/!'


output:
daw9udiwa9diuoawdj098awd89a0909w  opt/CHANGED/app-data/version.txt
wdalkwhjf8aufwaoif98fawfojaw98f8  opt/CHANGED/app-data/package.txt
awdhaw9d8yawdf8uaw9f8uwafhiuhawf  opt/CHANGED/bin/somefile/somefile
wdalkwhjf8aufwaoif98fawfojaw98f8  opt/CHANGED/bin/someapp/somefile

help appreciated. Thanks

Solution

A few issues with the current sed code:

• to expand OS variables the sed script must be wrapped in double quotes
• the use of ! as a delimiter may cause issues with some shells and/or shell configurations (eg, ! is a common shorthand for accessing the command line history)
• escaping the / is only needed when the / also serves as the sed script delimiter (ie, no need to escape / if using a different delimiter)

One sed idea that addresses these issues:

sed -e "s|opt/[^/]*|opt/$VAR|" input.txt

Where:

• opt/[^/]* - match on the string opt/ plus all characters that are not a \
• opt/$VAR - replace with the string opt/ plus the contents of the OS VAR variable

This generates:

daw9udiwa9diuoawdj098awd89a0909w  opt/CHANGED/app-data/version.txt
wdalkwhjf8aufwaoif98fawfojaw98f8  opt/CHANGED/app-data/package.txt
awdhaw9d8yawdf8uaw9f8uwafhiuhawf  opt/CHANGED/bin/somefile/somefile
wdalkwhjf8aufwaoif98fawfojaw98f8  opt/CHANGED/bin/someapp/somefile

Answered By - markp-fuso

Answer Checked By - Marie Seifert (WPSolving Admin)