shell duplicate spaces in file

Question

Is it possible to remove multiple spaces from a text file and save the changes in the same file using awk or grep?

Input example:
aaa     bbb  ccc
   ddd    yyyy

Output I want:
aaa bbb ccc
ddd yyyy

Does this answer your question? [How to remove extra spaces in bash?](https://stackoverflow.com/questions/13092360/how-to-remove-extra-spaces-in-bash) — Wiktor Stribiżew, Mar 31 '20 at 07:56
@nuclearwinter27 : `grep` does not modify any file. It reads files and writes to stdout. `awk` programs can create a file, but I am not aware that awk offers anything to update a file in-place; at least it was not designed for this. Some languages and tools (for instance `sed`, `ruby`, `perl`) make this task easy by simulating "in-place" editing. — user1934428, Mar 31 '20 at 08:39

RavinderSingh13 · Accepted Answer · 2020-03-31T08:10:23.100

2

Simply reset value of $1 to again $1 which will allow OFS to come into picture and will add proper spaces into lines.

awk '{$1=$1} 1' Input_file

EDIT: Since OP mentioned that what if we want to keep only starting spaces then try following.

awk '
match($0,/^ +/){
  spaces=substr($0,RSTART,RLENGTH)
}
{
  $1=$1
  $1=spaces $1
  spaces=""
}
1
'  Input_file

edited Mar 31 '20 at 08:10

answered Mar 31 '20 at 07:54

RavinderSingh13

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But if i have a text file ,how I can keep the alignment of the beginning of the lines? – nuclearwinter27 Mar 31 '20 at 08:06
@nuclearwinter27, Please try EDIT solution now and lemme now then? – RavinderSingh13 Mar 31 '20 at 08:10
1

@nuclearwinter27, In case of in place editing append ` > temp && mv temp Input_file` to my code. But make sure you run my mentioned command(in my post) to make sure all is coming well on terminal. – RavinderSingh13 Mar 31 '20 at 09:11

score 2 · Answer 2 · answered Mar 31 '20 at 08:25

Using sed

sed -i -E  's#[[:space:]]+# #g' < input file

For removing spaces at the start

sed -i -E  's#[[:space:]]+# #g; s#^ ##g' < input file

Demo:

$cat test.txt
aaa     bbb  ccc
   ddd    yyyy

Output I want:
aaa bbb ccc
ddd yyyy
$sed -i -E  's#[[:space:]]+# #g' test.txt 
$cat test.txt
aaa bbb ccc
 ddd yyyy

Output I want:
aaa bbb ccc
ddd yyyy
$

shell duplicate spaces in file

2 Answers2