Concatenating lines ending with '+' using awk

Shell Programming and Scripting
1

Hi,

I have an ASCII text file where some of the lines are ending with '+' character.

I have to concatenate the next successive line with those lines having the trailing '+' char by removing that char.

The below awk code has some problems to do this task:

awk '{while(sub(/\+$/,"")) { getline a; $0=$0 "\n" a; }; $0=$0 "\n"}'

Could anyone correct this code?

2

Something like this?

awk '/\+$/{sub("\+"," ");printf $0;next}1' file
3

sed ok?

sed -e :a -e '/\+$/N; s/\\\n//; ta'  infile > outfile
4

Hi,

Try this

awk 'BEGIN {ORS=""} {if (/\+/) { gsub(/\+$/,"",$0); print ; getline; print"\n"} else { print $0"\n"}}'

---------- Post updated at 07:10 AM ---------- Previous update was at 06:48 AM ----------

Hi Franklin,

Could you please explain me the below

awk '/\+$/{sub("\+"," ");printf $0;next}1' file
5 
 /regex/ {code in here; next} 1

means if the regex is true execute the code { } inside the anonymous block
next means skip on to the next record.
the { } 1 - the trailing 1 - means else print $0, because 1 evaluates to true

6

Thank you for all the posts.

But is it possible to tell how can I fix my code ?

awk '{while(sub(/\+$/,"")) { getline a; $0=$0 "\n" a; }; $0=$0 "\n"}'
7

Should be something like this:

awk '{if(sub(/\+$/,"")){ getline a; $0=$0 " " a; }}{print}' file
8 
gawk 1 RS='+\n' ORS='' file
9

good one, but it does not work when the consecutive lines have '+'. Also, can you please explain the logic behind this, if possible?

10

In that case you can use a while loop:

awk '{while(sub(/\+$/,"")){ getline a; $0=$0 " " a; }}{print}' file
11 
 #!/bin/bash  declare -i flag flag=0 while read -r LINE do   case "$LINE" in    *+)     LINE="${LINE%+*}"     printf "%s " $LINE     flag=1     continue   esac   [[ $flag == 1 ]] && echo "$LINE" && flag=0   [[ $flag == 0 ]] && echo "$LINE" done

---------- Post updated at 05:15 AM ---------- Previous update was at 05:12 AM ----------


#!/bin/bash

declare -i flag
flag=0
while read -r LINE
do
  case "$LINE" in
   *+)
    LINE="${LINE%+*}"
    printf "%s " $LINE
    flag=1
    continue
  esac
  [[ $flag == 1 ]] && echo "$LINE" && flag=0
  [[ $flag == 0 ]] && echo "$LINE"
done <"myfile"
12

Awesome!! could you please explain me the logic??
What is the difference between 'getline' and 'next' in awk?

13

If a line ends with a "+" sign the sub function returns a 1. In that case we get the next line, store it in the variable a, appends it to the previous line ($0) and try to substitute the next "+" ...and so on.

After a getline command, awk continues with the next statement after the getline command but after a next command awk continues with the first statement of the awk program.