Ttdfjt

I have this shellcheck warning I can't figure out:

In /mnt/e/bin/iconic line 540:
 printf "FALSE|" >> "$IconsRaw" # Select field number 1
 ^-- SC2129: Consider using cmd1; cmd2; >> file instead of individual redirects.

I've noticed many of us here use shellcheck to fix our bash scripts / shell commands so I hope the question is on topic.

As per comments posting relevant section of bash script:

 if [[ "$X" == "?" || "$Y" == "?" ]] ; then
 : # Bad X or Y offset usually "Link to Name.ext~" (backup name)
 else
 let i++
 printf "FALSE|" >> "$IconsRaw" # Select field number 1
 printf "%s|" "$i" >> "$IconsRaw" # 2
 printf "%s|" "$File##*/" >> "$IconsRaw"
 printf "%s|" "$Linkless" >> "$IconsRaw" # 4
 printf "%s|" "$Date" >> "$IconsRaw" # 5
 printf "%s|" "$X" >> "$IconsRaw" # 6
 echo "$Y" >> "$IconsRaw" # 7
 fi

Solution

Thanks to accepted answer and comments I've learned that shellcheck not only catches errors in your code, but also suggests performance improvements. In this case the filename $IconsRaw was being opened and closed many times with each printf and echo.

The more efficient bash code:

 # X,Y screen coordinates invalid on backup files ending with "~"
 ! [[ "$X" == "?" || "$Y" == "?" ]] && let i++; echo 
 "FALSE

I assume your script has multiple instances of >> "$IconsRaw". That message is suggesting redirecting the output only once and grouping the commands in a subshell. Presumably to avoid the overhead of opening and closing the file multiple times.

So, instead of this:

 printf "FALSE|" >> "$IconsRaw" # Select field number 1
 printf "%s|" "$i" >> "$IconsRaw" # 2
 printf "%s|" "$File##*/" >> "$IconsRaw"
 printf "%s|" "$Linkless" >> "$IconsRaw" # 4
 printf "%s|" "$Date" >> "$IconsRaw" # 5
 printf "%s|" "$X" >> "$IconsRaw" # 6
 echo "$Y" >> "$IconsRaw" # 7

This:

" "$File##*/" 
 printf "%s >> "$IconsRaw"

Bu that's also a needless repetition of printf and it is more efficient to just do:

printf '%s|%s|%s|%s|%s|%s|%sn' 
 'FALSE' "$i" "$File##*/" "$Linkless" 
 "$Date" "$X" "$Y" >> "$IconsRaw"