Select filename with highest version number

Question

highestVersion() {
    for TEST_PATH in `ls -a "$/TEMP"/*.flg`
    do
        echo " you are here"
        TEST_FILE=`basename "$TEST_PATH"`
        echo "$TEST_FILE"
    done
}

Below is the file TEST_FILE. In this case for example "RMG" is a book name having 4 version. How can I pick the file with latest version among these set of files and store it in a variable? How can I iterate through this, so that at the end, the variable should contain only the unique filename with highest version number?

ABC_EFG_FLOOL_DR3GCTEU_19951223_HANSHAKE_V03.flg
ABC_EFG_FLOOL_DR3GCTPC_19951223_HANSHAKE_V03.flg
ABC_RFTY_PICK_AMTY_19951223_HANSHAKE_V03.flg
ABC_JANE_PICK_AMTY_19951223_HANSHAKE_V02.flg
ABC_XYZ_RMG_19951223_HANSHAKE_V01.flg
ABC_XYZ_RMG_19951223_HANSHAKE_V02.flg
ABC_XYZ_RMG_19951223_HANSHAKE_V03.flg
ABC_XYZ_RMG_19951223_HANSHAKE_V11.flg
ABC_XYZ_ALG0_19951223_HANSHAKE_V02.flg
ABC_XYZ_SGFXMM_19951223_HANSHAKE_V03.flg
ABC_XYZ_STRIP_FULLREVAL_YU_1234_19951223_HANSHAKE_V02.flg
ABC_XYZ_STRIP_FULLREVAL_YU_1234_19951223_HANSHAKE_V03.flg

Answer 1

Since the version order is the same as the lexical order in your case, with a POSIX shell:

set -- ABC_XYZ_RMG_19951223_HANSHAKE_V*.flg
# now $1, $2... contain the files from the lowest version to highest.

shift "$(($# - 1))"
highest_version=$1

# or without shift:
eval "highest_version=\${$#}"

Or with zsh or recent versions of bash:

rmgs=(ABC_XYZ_RMG_19951223_HANSHAKE_V*.flg)
highest_version=${rmgs[-1]}

To do it with every file in the current directory (again with zsh or recent versions of bash (4.0 or above)):

highest_versions() (
  cd -P -- "$TEMP" || exit
  typeset -A a
  for f in *V??.flg; do
    a[${f%V??.flg}]=$f
  done
  printf '%s\n' "${a[@]}"
)

On your files, that gives:

ABC_XYZ_STRIP_FULLREVAL_YU_1234_19951223_HANSHAKE_V03.flg
ABC_XYZ_RMG_19951223_HANSHAKE_V11.flg
ABC_JANE_PICK_AMTY_19951223_HANSHAKE_V02.flg
ABC_XYZ_ALG0_19951223_HANSHAKE_V02.flg
ABC_XYZ_SGFXMM_19951223_HANSHAKE_V03.flg
ABC_RFTY_PICK_AMTY_19951223_HANSHAKE_V03.flg
ABC_EFG_FLOOL_DR3GCTEU_19951223_HANSHAKE_V03.flg
ABC_EFG_FLOOL_DR3GCTPC_19951223_HANSHAKE_V03.flg

With shells that don't support associative arrays, you can do the same by invoking a tool that does like awk:

highest_versions() (
  cd -P -- "$TEMP" || exit
  awk 'BEGIN{
    for (i = 1; i < ARGC; i++) {
      key = val = ARGV[i]
      sub(/V..\.flg/, "", key)
      a[key] = val
    }
    for (i in a) print a[i]
    exit}' *V??.flg
)

Answer 2

I like perl so I'll suggest a perlish solution:

#!/usr/bin/env perl
use strict;
use warnings;
my %highest_version_of;

for ( glob ( "*.flg" ) ) { 
    my ( $filename, $version ) = m/^(\w+)_V(\d+).flg/; 
    if ( $highest_version_of{$filename} //= 0 < $version ) { $highest_version_of{$filename} = $version }; 
}
foreach my $filename ( sort keys %highest_version_of ) {
    print "${filename}_$highest_version_of{$filename}.flg\n";
}