Make sed ask for confirmation before each replacement?

Question

Is there a way to make sed ask me for confirmation before each replace? Something similar to 'c' when using replace inside vim.

Does sed do this at all?

Answer 1

Doing it with sed would probably not be possible as it's a non-interactive stream editor. Wrapping sed in a script would require far too much thinking. It is easier to just do it with vim:

vim -c '%s/PATTERN/REPLACEMENT/gc' -c 'wq' file.in

---

Since it was mentioned in comments below, here's how this would be used on multiple files matching a particular filename globbing pattern in the current directory:

for fname in file*.txt; do
    vim -c '%s/PATTERN/REPLACEMENT/gc' -c 'wq' "$fname"
done

Or, if you first want to make sure that the file really contains a line that matches the given pattern first, before performing the substitution,

for fname in file*.txt; do
    grep -q 'PATTERN' "$fname" &&
    vim -c '%s/PATTERN/REPLACEMENT/gc' -c 'wq' "$fname"
done

The above two shell loops modified into find commands that do the same things but for all files with a particular name somewhere in or under some top-dir directory,

find top-dir -type f -name 'file*.txt' \
    -exec vim -c '%s/PATTERN/REPLACEMENT/gc' -c 'wq' {} \;

find top-dir -type f -name 'file*.txt' \
    -exec grep -q 'PATTERN' {} \; \
    -exec vim -c '%s/PATTERN/REPLACEMENT/gc' -c 'wq' {} \;

Or, using the original shell loops and having find feed pathnames into them:

find top-dir -type f -name 'file*.txt' -exec sh -c '
    for pathname do
        vim -c "%s/PATTERN/REPLACEMENT/gc" -c "wq" "$pathname"
    done' sh {} +

find top-dir -type f -name 'file*.txt' -exec sh -c '
    for pathname do
        grep -q "PATTERN" "$pathname" &&
        vim -c "%s/PATTERN/REPLACEMENT/gc" -c "wq" "$pathname"
    done' sh {} +

You do, in any case, not want to do something like for filename in $( grep -rl ... ) since

1. it would require that grep finishes running before even starting the first iteration of loop, which is inelegant, and
2. the pathnames returned by grep would be split into words on whitespaces, and these words would undergo filename globbing (this disqualifies pathnames that contains spaces and special characters).

Related:

• Understanding the -exec option of `find`

Answer 2

You can get this by doing such:

:%s/OLD_TEXT/NEW_TEXT/gc

Specifically, adding the c after the third delimiter.

Note that the 'c' option only works in Vim; you won't be able to use it with sed at the command line.

Answer 3

You could let sed do its thing on the file and then save the result to a temporary file which you can then interactively patch into the original file using sdiff (see http://www.gnu.org/software/diffutils/manual/diffutils.html#Invoking-sdiff):

sed -r 's/something/something_else/g' my_file > tmp_file
sdiff -o my_file -s -d my_file tmp_file

Answer 4

If you don't want to open and close vim a whole bunch as other answers suggest, you can do the entire operation in vim...

1: open all files containing your pattern:

vim $(grep -RIlZ 'pattern')

2) in vim replace your pattern in all open buffers (with confirmation):

:bufdo %s/pattern/replace/gce | update

These can even be combined like so

vim $(grep -RIlZ 'pattern') -c ':bufdo %s/pattern/replace/gce | update'

Answer 5

searchandreplace () {
if [ -z $2 ] ; then
    realpath * | xargs grep -ins --directories=skip --color=always "$1" | nl -s "."
else
    realpath * | xargs grep -ins --directories=skip --color=always "$1" | nl -s "."
    exp=$(realpath * | xargs grep -ins --directories=skip --color=never "$1" | cut -d':' -f1,2 | awk -F':' '{print $2 $1}' | sed -E "s|^[0-9]+|sed -i \'&s/|; s|//|/"$1"/"$2"/g\' /|")
    IFS=$'\n'
    for d in $exp
        do
        read -p "Exec $(echo -e -n "\033[1;31m$d\033[0m")? " -e REP
            if [ "$REP" = y ]; then
            echo `bash -c $d`;
            fi
    done
fi
}

If you feed this with single argument –searchandreplace "AAA"– it only searches for that string in the current directory, but if you feed it with double arguments –searchandreplace AAA BBB– then in addition to the above it also asks you to replace the first with the second "line by line" for every line.