Replacing first character in line in multi-line text column - r

Question

I am trying to replace the "o " with "• " in this text:
• Direct the Department’s technical
• Perform supervisory and managerial responsibilities as leader of the program
o Set direction to ensure goals and objectives
o Select management and other key personnel
o Collaborate with executive colleagues to develop and execute corporate initiatives and
department strategy
o Oversee the preparation and execution of department’s Annual Financial Plan and budget
o Manage merit pay
• Perform other duties as assigned
Since these are at the beginning of the line I've tried
test<- sub(test, pattern = "o ", replacement = "• ") # does not work
test<- gsub(test, pattern = "^o ", replacement = "• ") # does not work
test<- gsub(test, pattern = "o ", replacement = "• ") # works but it also replaces to to t•
Why does "^o " not work since it only appears at the beginning of each the line

Answer 1

Is this is all in a single value? If so, use a lookbehind to find o following either line breaks or string start:
test2 <- gsub(test, pattern = "(?<=\n|\r|^)o ", replacement = "• ", perl = TRUE)
cat(test2)
• Direct the Department’s technical
• Perform supervisory and managerial responsibilities as leader of the program
• Set direction to ensure goals and objectives
• Select management and other key personnel
• Collaborate with executive colleagues to develop and execute corporate initiatives and department strategy
• Oversee the preparation and execution of department’s Annual Financial Plan and budget
• Manage merit pay
• Perform other duties as assigned
Alternatively, split into individual values per line, then use your original regex:
test3 <- gsub(unlist(strsplit(test, "\n|\r")), pattern = "^o ", replacement = "• ")
test3
[1] "• Direct the Department’s technical"
[2] ""
[3] "• Perform supervisory and managerial responsibilities as leader of the program"
[4] ""
[5] "• Set direction to ensure goals and objectives"
[6] ""
[7] "• Select management and other key personnel"
[8] ""
[9] "• Collaborate with executive colleagues to develop and execute corporate initiatives and department strategy"
[10] ""
[11] "• Oversee the preparation and execution of department’s Annual Financial Plan and budget"
[12] ""
[13] "• Manage merit pay"
[14] ""
[15] "• Perform other duties as assigned"

Answer 2

You do not need any lookbehind here, use ^ with (?m) flag:
test <- gsub(test, pattern = "(?m)^o ", replacement = "• ", perl=TRUE)
The (?m) redefines the behavior of the ^ anchor that means "start of a line" if you specify the m flag.
See the online R demo:
test <- "• Direct the Department’s technical\n\no Set direction to ensure goals and objectives\n\no Select management and other key personnel"
cat(gsub(test, pattern = "(?m)^o ", replacement = "• ", perl=TRUE))
Output:
• Direct the Department’s technical
• Set direction to ensure goals and objectives
• Select management and other key personnel