How can I read words (instead of lines) from a file?

Question

I\'ve read this question about how to read n characters from a text file using bash. I would like to know how to read a word at a time from a file that looks like:

Answer 1

Ordinarily, you should read from a file using a while read -r line loop. To do this and parse the words on the lines requires nesting a for loop inside the while loop.

Here is a technique that works without requiring nested loops:

for word in $(<inputfile)
do
    echo "$word"
done

Answer 2

In the context given, where the number of words is known:

while read -r word1 word2 _; do
  echo "Read a line with word1 of $word1 and word2 of $word2"
done

If you want to read each line into an array, read -a will put the first word into element 0 of your array, the second into element 1, etc:

while read -r -a words; do
  echo "First word is ${words[0]}; second word is ${words[1]}"
  declare -p words # print the whole array
done

Answer 3

This can be done using AWK too:

awk '{for(i=1;i<=NF;i++) {print $i}}' text_file

Answer 4

The way to do this with standard input is by passing the -a flag to read:

read -a words
echo "${words[@]}"

This will read your entire line into an indexed array variable, in this case named words. You can then perform any array operations you like on words with shell parameter expansions.

For file-oriented operations, current versions of Bash also support the mapfile built-in. For example:

mapfile < /etc/passwd
echo ${MAPFILE[0]}

Either way, arrays are the way to go. It's worth your time to familiarize yourself with Bash array syntax to make the most of this feature.

Answer 5

The read command by default reads whole lines. So the solution is probably to read the whole line and then split it on whitespace with e.g. for:

#!/bin/sh

while read line; do
    for word in $line; do
        echo "word = '$word'"
    done
done <"myfile.txt"

Answer 6

In bash, just use space as delimiter (read -d ' '). This method requires some preprocessing to translate newlines into spaces (using tr) and to merge several spaces into a single one (using sed):

{
 tr '\n' ' ' | sed 's/  */ /g' | while read -d ' ' WORD
 do
  echo -n "<${WORD}> "
 done
 echo
} << EOF
Here you have some words, including * wildcards
that don't get expanded,
multiple   spaces   between   words,
    and lines with spaces at the begining.
EOF

The main advantage of this method is that you don't need to worry about the array syntax and just work as with a for loop, but without wildcard expansion.