Bash detect an error in loop then continue processing

Question

I would like to process a list of Homebrew formulas contained in a text file. If there is an installation error (e.g. already install, bad formula name), I'd like it to write the error, but continue processing. The Github project.

What I have so far:

...
# process list of formulas that have been installed
for i in $(cat $FILE) ; do

    echo "Installing $i ..."

    # attempt to install formula; if error write error, process next formula

    brew install $i

done
...

How do I do this?

Answer 1

Does it help?

...
# process list of formulas that have been installed
for i in $(< "$FILE") ; do

    echo "Installing $i ..."

    # attempt to install formula; if error write error, process next formula

    brew install "$i" || continue

done
...

Note that if formula contains blanks then the for loop will split the line. It might be better to write:

...
# process list of formulas that have been installed
while read i ;  do

    # Jump blank lines
    test -z "$i" && continue

    echo "Installing $i ..."

    # attempt to install formula; if error write error, process next formula

    brew install "$i" || continue

done < "$FILE"
...

Answer 2

That should be simple.

# process list of formulas that have been installed
for i in $(<"$FILE") ; do

    echo "Installing $i ..."

    # attempt to install formula; if error write error, process next formula

    if ! brew install $i
    then
        echo "Failed to install $i"
        continue
    fi

done

Adding an if statement to the installation part will check for the exit status of brew and if it failed then will report and error and continue.