print the last letter of each word to make a string using `awk` command

Question

I have this line

UDACBG UYAZAM DJSUBU WJKMBC NTCGCH DIDEVO RHWDAS

i am trying to print the last letter of each word to make a string using awk command

awk '{ print substr($1,6) substr($2,6) substr($3,6) substr($4,6) substr($5,6) substr($6,6) }'

In case I don't know how many characters a word contains, what is the correct command to print the last character of $column, and instead of the repeding substr command, how can I use it only once to print specific characters in different columns

Answer 1

If you have just this one single line to handle you can use

awk '{for (i=1;i<=NF;i++) r = r "" substr($i,length($i))} END{print r}' file

If you have multiple lines in the input:

awk '{r=""; for (i=1;i<=NF;i++) r = r "" substr($i,length($i)); print r}' file

Details:

• {for (i=1;i<=NF;i++) r = r "" substr($i,length($i)) - iterate over all fields in the current record, i is the field ID, $i is the field value, and all last chars of each field (retrieved with substr($i,length($i))) are appended to r variable
• END{print r} prints the r variable once awk script finishes processing.
• In the second solution, r value is cleared upon each line processing start, and its value is printed after processing all fields in the current record.

See the online demo:

#!/bin/bash
s='UDACBG UYAZAM DJSUBU WJKMBC NTCGCH DIDEVO RHWDAS'
awk '{for (i=1;i<=NF;i++) r = r "" substr($i,length($1))} END{print r}' <<< "$s"

Output:

GMUCHOS