using BASH how can i replace all text between two patterns containing forward slashes?-CodePudding

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

CodePudding user response：

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

CodePudding user response：

If you are open to using awk rather than sed, the following may work for you:

$ awk -v rep="CHANGED" -F/ 'BEGIN{OFS="/"} {$2=rep; print}' file1 
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

Split each line on the forward slash character and replace the second field with your desired replacement text. Then format the output with the output field separator (OFS) set as a forward slash.