Enhance install script to handle commented and uncommented lines (#3632)

[buttering]

Enhance install script to handle commented and uncommented lines in shell file with user prompts for modification.

• Track commented and uncommented lines in the file.
• Prompt user to append or skip if the line is commented.
• Ensure new lines are added only when necessary, based on user input.
• To the fish_user_key_bindings.fish, the original logic would append the line to the end if no corresponding statement was found. I’ve adopted the same behavior for commented lines.

This is my first contribution to this open-source project, and I’m really excited to get involved.
I saw the discussion in issue #3632 and wanted to try implementing the proposed feature.
One concern I have is whether I should write test cases for this change. The existing Ruby tests seem not to support testing the fzf installation process directly. Additionally, I worry that the logic in the updated code might be a bit complex (though I’ve tried my best to keep it readable).
Please feel free to provide feedback on my changes. If there’s anything I can improve, I’d greatly appreciate your guidance.

[junegunn]

Thanks for your interest in this project. If we're going to display the matching lines, we can just use the output of the grep comment.

Here's my take on the problem. What do you think?

diff --git a/install b/install
index 5b67e30..607c7ef 100755
--- a/install
+++ b/install
@@ -295,35 +295,43 @@ EOF
 fi
 
 append_line() {
-  set -e
-
-  local update line file pat lno
+  local update line file pat lines
   update="$1"
   line="$2"
   file="$3"
   pat="${4:-}"
-  lno=""
+  lines=""
 
   echo "Update $file:"
   echo "  - $line"
   if [ -f "$file" ]; then
     if [ $# -lt 4 ]; then
-      lno=$(\grep -nF "$line" "$file" | sed 's/:.*//' | tr '\n' ' ')
+      lines=$(\grep -nF "$line" "$file")
     else
-      lno=$(\grep -nF "$pat" "$file" | sed 's/:.*//' | tr '\n' ' ')
+      lines=$(\grep -nF "$pat" "$file")
     fi
   fi
-  if [ -n "$lno" ]; then
-    echo "    - Already exists: line #$lno"
-  else
-    if [ $update -eq 1 ]; then
-      [ -f "$file" ] && echo >> "$file"
-      echo "$line" >> "$file"
-      echo "    + Added"
-    else
-      echo "    ~ Skipped"
+  if [ -n "$lines" ]; then
+    echo "    - Already exists:"
+    sed 's/^/        Line /' <<< "$lines"
+
+    update=0
+    if [ $(\grep -vn "^[0-9]*:[[:space:]]*#" <<< "$lines" | wc -l) -eq 0 ]; then
+      echo "    - But they all seem to be commented"
+      ask "    - Continue modifying $file?"
+      update=$?
     fi
   fi
+
+  set -e
+  if [ $update -eq 1 ]; then
+    [ -f "$file" ] && echo >> "$file"
+    echo "$line" >> "$file"
+    echo "    + Added"
+  else
+    echo "    ~ Skipped"
+  fi
+
   echo
   set +e
 }

Update /Users/jg/.bashrc:
  - [ -f ~/.fzf.bash ] && source ~/.fzf.bash
    - Already exists:
        Line 520:[ -f ~/.fzf.bash ] && source ~/.fzf.bash # This one is NOT commented
        Line 521:# [ -f ~/.fzf.bash ] && source ~/.fzf.bash # This one is commented
    ~ Skipped

Update /Users/jg/.bashrc:
  - [ -f ~/.fzf.bash ] && source ~/.fzf.bash
    - Already exists:
        Line 520:# [ -f ~/.fzf.bash ] && source ~/.fzf.bash # This one is commented
        Line 521:  # [ -f ~/.fzf.bash ] && source ~/.fzf.bash # This one is also commented
    - But they all seem to be commented
    - Continue modifying /Users/jg/.bashrc? ([y]/n) n
    ~ Skipped

[junegunn]

One concern I have is whether I should write test cases for this change. The existing Ruby tests seem not to support testing the fzf installation process directly.

No, we currently don't test install script. So don't worry about it. The importance of the script has declined since most users use a package manager to install fzf, and setting up shell integration is much easier now than it used to be, and it's feasible to manually add a single line to your shell configuration file.

https://github.com/junegunn/fzf/blob/master/README.md#setting-up-shell-integration

[buttering]

I’ve learned a lot about Shell scripting from your explanation. I truly admire the elegance and simplicity of your code.

[junegunn]

Merged, thanks for taking the initiative!