pattern matching using gsub

I am trying to search and replace multiple patterns of a string and replace it with different values. However the command is replacing only one pattern and ignoring the rest.

output=$(echo "$output4" | awk 'NR>1 {gsub(/\[|]/,""); gsub("+r","READ"); gsub("+r+w","READ and WRITE"); gsub("+r+w+g","READ, WRITE and GRANT"); print}')

When I execute the script, this is what I am getting.

    Group Analyst_Corp in security domain Native: READ. Group Finance_Dev in security domain Native: READ+w. Manufacturing_Corp in security domain Native: READ+w
Information_Tech in security domain Native: READ+w+g.

I am looking for the output like this.

        Group Analyst_Corp in security domain Native: READ. Group Finance_Dev in security domain Native: READ and WRITE. Manufacturing_Corp in security domain Native: READ and WRITE
    Information_Tech in security domain Native: READ, WRITE and GRANT.

Guessing at OP's input (ie, contents of the output4 variable), and throwing in some [ and ] characters for good measure:

output4="Some line to ignore
    Group [Analyst_Corp] in security domain [Native]: +r. Group [Finance_Dev] in security domain [Native]: +r+w. [Manufacturing_Corp] in security domain [Native]: +r+w
[Information_Tech] in security domain [Native]: +r+w+g."

There are a few issues with the current code:

• where patterns overlap in content you want to replace the longer strings (eg, +r+w+g) before replacing the shorter strings (eg, +r)
• the + has a special meaning in regex patterns so to match on a literal + we need to escape it (\+ or [+])
• when escaping with \ you'll run into fewer issues if you work with a static regex (pattern wrapped in a pair of / characters)
• when escaping with [] you can use a dynamic (pattern wrapped in double quotes) or static regex
• while the current code works for removing brackets ([, ]) we'll swap in a different regex that's a tad easier (?) to read/understand

A few different options for modifying OP's current code:

########
# static regex; using `\` to escape the '+'

awk 'NR>1 { gsub(/[][]/,"")                             # remove brackets '[' and ']'
            gsub(/\+r\+w\+g/,"READ, WRITE and GRANT")
            gsub(/\+r\+w/,"READ and WRITE")
            gsub(/\+r/,"READ")
            print
          }
' <<< "${output4}"

########
# dynamic regex; using '[]' to escape the '+'

awk 'NR>1 { gsub(/[][]/,"")
            gsub("[+]r[+]w[+]g","READ, WRITE and GRANT")
            gsub("[+]r[+]w","READ and WRITE")
            gsub("[+]r","READ")
            print
          }
' <<< "${output4}"

########
# static regex; using '[]' to escape the '+'

awk 'NR>1 { gsub(/[][]/,"")
            gsub(/[+]r[+]w[+]g/,"READ, WRITE and GRANT")
            gsub(/[+]r[+]w/,"READ and WRITE")
            gsub(/[+]r/,"READ")
            print
          }
' <<< "${output4}"

All of these generate:

    Group Analyst_Corp in security domain Native: READ. Group Finance_Dev in security domain Native: READ and WRITE. Manufacturing_Corp in security domain Native: READ and WRITE
Information_Tech in security domain Native: READ, WRITE and GRANT.

Collapsing down to one-liners and storing results in variable output:

output=$(awk 'NR>1 {gsub(/[][]/,""); gsub(/\+r\+w\+g/,"READ, WRITE and GRANT"); gsub(/\+r\+w/,"READ and WRITE"); gsub(/\+r/,"READ"); print} ' <<< "${output4}")

output=$(awk 'NR>1 {gsub(/[][]/,""); gsub("[+]r[+]w[+]g","READ, WRITE and GRANT"); gsub("[+]r[+]w","READ and WRITE"); gsub("[+]r","READ"); print} ' <<< "${output4}")

output=$(awk 'NR>1 {gsub(/[][]/,""); gsub(/[+]r[+]w[+]g/,"READ, WRITE and GRANT"); gsub(/[+]r[+]w/,"READ and WRITE"); gsub(/[+]r/,"READ"); print} ' <<< "${output4}")

All of these generate:

$ typeset -p output
declare -- output="        Group Analyst_Corp in security domain Native: READ. Group Finance_Dev in security domain Native: READ and WRITE. Manufacturing_Corp in security domain Native: READ and WRITE
    Information_Tech in security domain Native: READ, WRITE and GRANT."