Condensing multiple spaces in given linux file name without using sed or tr (bash)

Question

I need to write a function that does the following: the function receives file names with this format *.station

Between the words might be multiple spaces, I want to remove the extra spaces between the words and leave only one.

For example (1): aa__________a____aa _____________ ssd________.station, needs to be changed to aa_a_aa_ssd.station

(2): aa______________a.station needs to be written as: aa_a.station

(The underscores (_) signify spaces in the above.)

i am not allowed to use tr unfortunately – evgniy tayarov Aug 22 '17 at 17:50 — evgniy tayarov, Aug 22 '17 at 17:50
Why are you "not allowed" to use tr? Is this homework? – Wildcard Aug 22 '17 at 19:50 — Wildcard, Aug 22 '17 at 19:50

Hauke Laging · Answer 1 · 2017-08-22T19:45:54.617

1

shopt -s extglob
file="aa     a       a.station"
echo mv "$file" "${file// +( )/ }"

An alternative would be a loop with

"${file//  / }"

until there are only single spaces left:

file="a                      a"

last_run=""
new="$file"
while [ "$last_run" != "$new" ]; do
        last_run="$new"
        new="${last_run//  / }"
done

echo mv "$file" "$new"

Or with word splitting:

IFS=" "
mv "$file" "$(echo $file)"

edited Aug 22 '17 at 19:45

answered Aug 22 '17 at 18:01

Hauke Laging

90,279

can you please explain how do i write that loop? assuming all the *.station files are in the current directory. – evgniy tayarov Aug 22 '17 at 18:15
@evgniytayarov see: https://unix.stackexchange.com/q/162586/117549 – Jeff Schaller Aug 22 '17 at 18:23
and/or https://unix.stackexchange.com/q/97084/117549 – Jeff Schaller Aug 22 '17 at 18:24

score 0 · Answer 2 · edited Aug 22 '17 at 18:33

0

#!/bin/bash
file="aa     a       a.station"
read -r -a myarray <<< "$file"
printf  "${myarray[*]}"

This reads a string into an array, splitting on the standard IFS characters (space, tab, newline). The entire array, each element, now with single delimiters, is then printed.

You can also leverage xargs:

#!/bin/bash
file="aa     a       a.station"
newfile=$(echo $file|xargs)
printf  "${newfile}"

edited Aug 22 '17 at 18:33

ilkkachu

138,973

answered Aug 22 '17 at 18:25

JRFerguson

14,740

Why the effort with read? myarray=($file) And IFS should be set to space only. – Hauke Laging Aug 22 '17 at 19:43

Condensing multiple spaces in given linux file name without using sed or tr (bash)

2 Answers2