CODEWITHSUNDEEP
linuxbash
Cesar Ortiz
Cesar Ortiz

Reputation: 932

Combine two text files in bash script

I have a text file (FILE_A.txt) with this content:

Content1
Content2
Content3

And other text file (FILE_B.txt) with this content:

A[#]
B[#]
C[#]

I would like to combine FILE_A.txt and FILE_B.txt in other file (FILE_C.txt) in this way:

A[Content1]
B[Content2]
C[Content3]

How could I make this using bash shell in linux (sed, cut, grep, etc)?

Upvotes: 2

Views: 2671

Answers (3)

Shawn Chin
Shawn Chin

Reputation: 86844

The following reads both files concurrently, one line at a time, and store the lines in $value and $template. We then use bash's variable substring replacement to replace # within $template with the contents of $value.

exec 6<"FILE_B.txt"  # open file for reading and assign file descriptor 6

while read -r value; do  # loop through FILE_A.txt, storing each line as $value
  read -r template <&6   # read a line from FILE_B.txt, store as $template
  echo ${template/\#/$value}  # replace value into the template in place of `#`
done <"FILE_A.txt"

exec 6<&-  # close input file descriptor 6

Upvotes: 2

ghoti
ghoti

Reputation: 46826

Here we go.

# awk 'NR==FNR{a[NR]=$0;next;} sub(/#/,a[FNR])' FILE_A.txt FILE_B.txt
A[Content1]
B[Content2]
C[Content3]

How does this work?

  • NR==FNR - causes the following statements to be run if the record number matches the FILE record number - that is, we are currently reading only the firs tfile.
  • {a[NR]=$0;next;} - Store values from the first file in an array.
  • sub(/#/,a[FNR]) - Once we're in the second file, substitute # for the matching value stored from the first file. Note that this isn't inside curly brackets, so it's being evaluated as a condition. If the sub() statement succeeds, the current line is printed.

Upvotes: 3

dogbane
dogbane

Reputation: 274532

Use paste and sed as follows:

$ paste File_B.txt File_A.txt | sed 's/#]\s*\(.*$\)/\1]/g'
A[Content1]
B[Content2]
C[Content3]

Upvotes: 2

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