CODEWITHSUNDEEP
linuxbashunix
Yash
Yash

Reputation: 71

Extracting text from a file and appending the contents at the end of each line in unix

I want to do as follows in a .txt file. Contents of file.txt are:

w|x|y|z
w1|x1|y1|z1
w2|x2|y2|z2

Required result:

w|x|y|z|w_x
w1|x1|y1|z1|w1_x1
w2|x2|y2|z2|w2_x2

I wish to append the first two pipe seperated words to be appended at the end of each line with a underscore(_) between them in the same file.

Upvotes: 0

Views: 55

Answers (3)

choroba
choroba

Reputation: 241828

You can use sed:

sed 's/^\([^|]*\)|\([^|]*\).*/&|\1_\2/' file.txt
#         ~~~~~     ~~~~~  ~~ ^   ^ ^
#          1st      2nd  Rest |   | |
#         column  column     All 1st|
#                                   2nd

or Perl:

perl -plaF'/\|/' -e '$_ .= "|$F[0]_$F[1]"' -- file.txt
  • -p reads the input line by line and prints the output
  • -l removes newlines from input and adds them to output
  • -a split input into the @F array
  • -F specifies the separator for -a

Upvotes: 4

DevilaN
DevilaN

Reputation: 1464

Using purely bash text processing simple commands:

cut -d '|' -f 1,2 --output-delimiter='_' t.txt | paste -d '|' t.txt -

If your data is in t.txt file.

Explanation:

  • First part (with cut) takes 1st and 2nd column from file and joins them with '_' (output delimiter)
  • paste joins original file with output from the previous command, line by line, using '|' delimiter (notice - mark which is used as standard input taken from piped data from cut command)

Upvotes: 1

William Pursell
William Pursell

Reputation: 212238

The "advantage" of perl and (gnu) sed is that they offer an option to overwrite the file with the output, which seems to be the OPs desire. The disadvantage is that they offer such an option which prevents the user from appreciating that such a thing is not the Unix Way (TM). Do this with awk, and use the shell to redirect the output as desired (eg, write a temp file and move it if desired). 

awk '{print $0,$1 "_" $2}' OFS=\|  FS=\| file.txt

Upvotes: 1

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