Append strings to multiple space-separated values in a variable

Question

I have a variable VAR="XYZ YZA ZAB" declared and I would like to append some strings next to all the words in that variable.

For example: I want to append .file1 to each space-separate substring in XYZ YZA ZAB.

The output of variable should be as below without any for loop or anything.

VAR="XYZ.file1 YZA.file1 ZAB.file1" 

I am sure awk can be used, but I am not aware of how to use it for this purpose.

Answer 1

With ksh93:

VAR2=${VAR//+([^[:space:]])/\1.file1} 

Same with zsh:

set -o extendedglob VAR2=${VAR//(#m)[^[:space:]]##/$MATCH.file1} 

POSIXly:

VAR2=$(printf '%s\n' "$VAR" | sed 's/[^[:space:]]\{1,\}/&.file1/g') 

(beware it strips trailing newline characters if any in $VAR).

They all substitute sequences of one or more (+(...), ##, \{1,\}) characters other than white space ones ([^[:space:]]) with the same thing (\1, $MATCH, &) and .file1 appended.

Or you could split and join if you don't care about preserving the amount of white space between words and words are separated by SPC, TAB and NL (and not other whitespace characters) only:

unset IFS # default IFS of SPC+TAB+NL set -o noglob # disable glob set -- $VAR # split+glob without glob for i do set -- "$@" "$i.file1" # add suffix shift done VAR2="$*" # join with space 

---

With shells with array support, you may want to use an array variable instead of a scalar one. With rc/es/zsh/ksh93/bash/mksh/yash:

VAR=(XYZ YZA ZAB) 

Then adding .file1 to each element (which this time may contain white space themselves) is just a matter of:

VAR2=($VAR^.file1) # rc, es VAR2=($^VAR.file1) # zsh VAR2=("${VAR[@]/*/\0.file1}") # ksh93 VAR2=("${VAR[@]/%/.file1}") # bash 

Answer 2

The simple solution will be to use the shell splitting capability (with a default IFS):

$ set -f; printf '%s.file1 ' $var; echo XYZ.file1 YZA.file1 ZAB.file1 

Understand that that will collapse repeated spaces/tabs to one and that it will remove leading and trailing white-space. The set -f will avoid problems with filenames that contain glob characters (* ? or [). The printed string in this case will have an additional space.

Answer 3

With zsh, here is a way a little bit shorter than the one from Stéphane:

$ VAR="XYZ YZA ZAB" $ VAR=( ${^=VAR}.file ) $ print -l $VAR XYZ.file YZA.file ZAB.file 

= performs word splitting of the string then ^ "distribute" the suffix to each words.

http://zsh.sourceforge.net/Doc/Release/Expansion.html#Parameter-Expansion