Score:1

Ubuntu

Bash string split by delimiter constrained by number of characters

Bruno Henrique Peixoto

6/1/23, 5:02 PM

I want to split a long text separated by spaces through bash, but I fail. The command below splits into characters, but not delimiters.

echo "The quick fox jumped over the lazy dog" | fold -w 10
echo "The quick fox jumped over the lazy dog" | sed -e 's/.\{9\}/&\n/g'

It would be nice to have it for some user bash interaction.

Input syntax

format_text 10 "The quick fox jumped over the lazy dog"

Output:

The quick 
fox jumped 
over the 
lazy dog

You must notice that the third line would cut "l" letter from "lazy" off if not for spacing spacing rule.

Update: The current result is good, There is some issue with the work slicer I cannot get by myself: it does not break words before the limit is transpassed.

#!/bin/bash

printHeader () {
    declare -i line_length=$3
    
    # Upper and lower fences 
    local upper_command="print \"$1\" *" 
    local upper_fence="$(python -c "$upper_command $line_length")"
    
    local lower_command="print \"$2\" *"
    local lower_fence="$(python -c "$lower_command $line_length")"
    
    # Slice words by some chracter counter
    local regex_counter="s/(.{$line_length}) /\1\n/g"
    
    # Complete line with dots and a pipe
    local res="$line_length - length"
    local repeat_pattern='$(repeat res \".\"; echo)'
    local fill_command="{res=($res); printf \"%s%s|\n\", $0, $repeat_pattern}"

    echo "$upper_fence"

    sed -r "$regex_counter" <<< $4

    echo "$lower_fence"
}

printHeader "#" "#" 10 "The quick fox jumped over the lazy dog"

Current output without final token:

##########
The quick fox
jumped over
the lazy dog
##########

135

0 + 0

command-line

bash

text-processing

Bruno Henrique Peixoto

6/1/23, 7:10 PM

I added the examples as you suggested

Bruno Henrique Peixoto

6/1/23, 7:45 PM

Great question! It is an open question for the problem. We may tag the line with a <<-- at the end, or something like that. Or maybe break the word relentlessly.

Bruno Henrique Peixoto

6/1/23, 7:47 PM

But lets take the case where the number of characters is greater than the greatest word. It seems reasonable for a natural language text,

bac0n

6/1/23, 8:01 PM

`| fmt -w 11` .. (think you have to count the newline too)

Bruno Henrique Peixoto

6/1/23, 8:13 PM

Sublime answer. It is already ok for me! In case I want to put some delimiter to denote the line limit, does the code changes much?

Score:2

Ubuntu

pa4080

6/1/23, 9:02 PM

sed -r 's/([^ .]+ [^ .]+) /\1\n/g' <<< "The quick fox jumped over the lazy dog"

The quick
fox jumped
over the
lazy dog

The character set [^ .]+ means one or more + characters of any kind . excluding the ^ whitespaces. So the capture group ([^ .]+ [^ .]+) matches for patterns as string string. The whole regular expression has an additional whitespace at the end ([^ .]+ [^ .]+) (it could be included in the capture group in order to preserve it).

With sed by using the substitute s command we replace the matched pattern by the content of the first capture group \1 and a new line character \n instead of the whitespace. By the flag g we repeat the command to the end of each line. The -r option activates the extended regular expressions.

Update - this is the actual answer:

sed -r 's/(.{8}) /\1\n/g' <<< "How do we know it is going to match the pre-defined number of characters?"

How do we
know it is
going to
match the
pre-defined
number of
characters?

In this example we capture strings with length at least 8 characters (including whitespaces) followed by a whitespace. We can check the actual length of the output lines in a way as this:

sed -r 's/(.{8}) /\1\n/g' <<< "How do we know it is going to match the pre-defined number of characters?" \
    | awk '{print length}'

And by the help of the answers of the question How to use printf to print a character multiple times? [awk] we can achieve the desired result.

sed -r 's/(.{8}) /\1\n/g' <<< "How do we know it is going to match the pre-defined number of characters?" \
    | awk '{rest=(12 - length); printf "%s%s|\n", $0, substr(".........", 1, rest)}'

How do we...|
know it is..|
going to....|
match the...|
pre-defined.|
number of...|
characters?.|

In case you want to break the words remove the final whitespace from the above regular expression /(.{8})/. Here is an example where the max line length will be exactly 10 characters or less, where the second sed command will trim the whitespaces around each new line.

sed -r 's/(.{10})/\1\n/g' <<< "How do we know it is going to match the pre-defined number of characters?" \
    | sed -r 's/(^ | $)//g' \
    | awk '{rest=(10 - length); printf "%s%s|\n", $0, substr(".........", 1, rest)}'

How do we.|
know it is|
going to..|
match the.|
pre-define|
d number o|
f characte|
rs?.......|

0 + 0

Bruno Henrique Peixoto

6/1/23, 9:42 PM

How do we know it is going to match the pre-defined number of characters?

pa4080

6/1/23, 9:56 PM

Hi, @BrunoHenriquePeixoto. I've updated the answer with little joke of your question.

Bruno Henrique Peixoto

6/1/23, 9:57 PM

GREAT! The last last wish, genius. May you put a cherry on the top by delimiting the last character (either {max_val} or {max_val+1}). May be some symbol | or #, does not matter.

pa4080

6/1/23, 10:10 PM

@BrunoHenriquePeixoto, I didn't understand this requirement. Probably you need a second expression as: `sed -r -e 's/(.{8}) /\1\n/g' -e 's/(.)$/\|\1/'` but I'm not sure. Or if you want to modify each new line the laziest way is by a second processing as: `sed -r 's/(.{8}) /\1\n/g' in-file.txt | sed -r 's/(.)$/\|\1/'`

Bruno Henrique Peixoto

6/1/23, 10:14 PM

Example: Given your profile name "pa4080" (6 digits), the maximum number of 10 line digits and delimiter pipe '|', and dots for trailing space, the output must be "pa4080....|", without the double quotes.

pa4080

6/1/23, 10:57 PM

@BrunoHenriquePeixoto, please check the update :)

Bruno Henrique Peixoto

6/1/23, 11:07 PM

You should be on stack oveflow hall of fame

Bruno Henrique Peixoto

6/1/23, 11:36 PM

The substr snippet seems a little sloppy. Some repeat routine suits better. We did a great job!

Bruno Henrique Peixoto

6/2/23, 12:22 AM

There is an issue with the sed we implemented. Take a look at the main body of the post.

pa4080

6/2/23, 8:01 AM

Hi, @BrunoHenriquePeixoto, if you want to break the word try to remove the final whitespace from the regex: `/(.{8}) /` => `/(.{8})/`. I've added an update to the answer.

Bruno Henrique Peixoto

6/2/23, 11:13 AM

I want to give more cotes to the answer! :(! THANKS

Bruno Henrique Peixoto

6/2/23, 11:25 AM

votes, hugs, money, calories, credit, stars, whatever counts

pa4080

6/2/23, 12:47 PM

@BrunoHenriquePeixoto, you can just upvote it by clicking at the arrow up :)

Bruno Henrique Peixoto

6/2/23, 1:21 PM

I will upvote every day of my life.

Bruno Henrique Peixoto

6/2/23, 1:22 PM

Your reward: https://github.com/brunolnetto/engage

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Bash string split by delimiter constrained by number of characters

TH: สตริง Bash แบ่งตามตัวคั่นที่จำกัดด้วยจำนวนอักขระ

RO: Șirul Bash împărțit de delimitator constrâns de numărul de caractere

RU: Строка Bash, разделенная разделителем, ограниченным количеством символов

VI: Chuỗi Bash được phân tách bằng dấu phân cách bị ràng buộc bởi số lượng ký tự

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