How to replace multiple spaces by one tab

Question

Ive some textfiles which contains some colums seperated by a various number of spaces, but instead i need one single tab as a seperator. Any ways in Bash?

Answer 1

To convert sequences of more than one space to a tab, but leave individual spaces alone:

sed 's/ \+ /\t/g' inputfile > outputfile

To do this for a number of files:

for inputfile in *
do
    sed 's/ \+ /\t/g' "$inputfile" > tmpfile && mv tmpfile "$inputfile"
done

or

for inputfile in *
do
    sed -i .bak 's/ \+ /\t/g' "$inputfile"
done

or

find . -type f -exec sed -i .bak 's/ \+ /\t/g' "$inputfile" \;

Answer 2

The easiest answer using only bash is:

while read -r col1 col2 col3 ...; do
    echo -e "$col1\t$col2\t$col3..."
done <file

If there are a variable number of columns, you can do this, but it will only work in bash, not sh:

while read -r -a cols; do
    (
        IFS=$'\t'
        echo "${cols[*]}"
    )
done <file

e.g.

while read -r -a cols; do
    (
        IFS=$'\t'
        echo "${cols[*]}"
    )
done <<EOF
a b   c
d   e    f
  g h i
EOF

produces:

a   b   c
d   e   f
g   h   i

(there is a tab in between each, but it's hard to see when I paste it here)

You could also do it using sed or tr, but notice that the handling of blanks at the start produces different results.

sed:

$ sed 's/  */\t/g' << EOF
a b   c
d   e    f
  g h i
EOF
a       b       c
d       e       f
        g       h       i

tr:

$ tr -s ' ' '\t' <<EOF
a b   c
d   e    f
  g h i
EOF
a       b       c
d       e       f
        g       h       i

Answer 3

perl -p -i -e 's/\s+/\t/g' *.txt

Answer 4

Try the following SED script:

 sed 's/  */<TAB>/g' <spaces-file > tabs-file

Where <TAB> is pressing the TAB key.

Answer 5

You can use sed to replace a number of spaces with a tab.:

Example to replace one-or-more-spaces with one tab:

cat spaced-file | sed 's/ \+/\t/g' > tabbed-file