Is it possible to sort the letters in a word in a line of text?

Another perl variant:

$ perl -pe 's{^rap ,\K\S+}{join "", sort split //, $&}e' file rap ,Xfgl MIT X11 rap ,BPXfl 'MITER' rap ,Bfgl share git-grep rap ,bfl X11 rap ,Bfl xzfgrep rap ,Bf X11 

For your extra requirement of having lower case letters before upper case ones, you can rely on the fact that in ASCII, 'x' is 'X' ^ 32 (and 'X' is 'x' ^ 32):

$ perl -pe 's{^rap ,\K\S+}{join "", sort {(ord($a)^32) <=> (ord($b)^32)} split //, $&}e' file rap ,fglX MIT X11 rap ,flBPX 'MITER' rap ,fglB share git-grep rap ,bfl X11 rap ,flB xzfgrep rap ,fB X11 

Using GNU awk for sorted_in and, since we're using gawk anyway, a few other convenient but unnecessary extensions, we can apply the Decorate-Sort-Undecorate idiom by putting 1 in front of any lower case chars and 2 in front of upper to force the lower case ones to all sort before upper case and then remove those decorations again before printing:

$ cat tst.awk BEGIN { PROCINFO["sorted_in"] = "@val_str_asc" } match( $0, /^(\s*\S+\s*,)(\S+)(.*)/, a ) { gsub( /[[:lower:]]/, "1 &,", a[2] ) # Decorate gsub( /[[:upper:]]/, "2 &,", a[2] ) sorted = "" split(a[2],opts,",") for ( idx in opts ) { # Sort sorted = sorted opts[idx] } gsub( /[[:digit:] ,]/, "", sorted ) # Undecorate $0 = a[1] sorted a[3] } { print } 

$ awk -f tst.awk file rap ,fglX MIT X11 rap ,flBPX 'MITER' rap ,fglB share git-grep rap ,bfl X11 rap ,flB xzfgrep rap ,fB X11 

Using Raku (formerly known as Perl_6)

Alphabetize letter options in ASCII-order (uppercase first):

~$ raku -pe 's{ <?after \, > (\w+) } = "{$0.comb.sort.join}";' file 

Raku is a programming language in the Perl-family that features high-level support for Unicode built-in. Above is a Raku translation of excellent Perl code by @steeldriver (with a nod to @StéphaneChazelas).

• The s/// form can be written s{ … } = " … ". Curlies in the replacement half (inside the doublequotes) signify a code block that runs on the capture.
• Captures in Raku start from $0.
• A positive lookbehind "Y-after-X" in Raku is written <?after X > Y (the negative uses a ! instead of a ?).
• Raku implements a positive (global) selector function comb, that--absent a regex argument--breaks on every character.

Sample Input:

rap ,Xflg MIT X11 rap ,XPBfl 'MITER' rap ,Bflg share git-grep rap ,bfl X11 rap ,Bfl xzfgrep rap ,Bf X11 

Sample Output (1):

rap ,Xfgl MIT X11 rap ,BPXfl 'MITER' rap ,Bfgl share git-grep rap ,bfl X11 rap ,Bfl xzfgrep rap ,Bf X11 

Alphabetize letter options with lowercase first:

~$ raku -pe 's{ <?after \, > (\w+) } = "{ my (@l,@u); $0.comb.map({ /<:Ll>/ ?? @l.push($_) !! @u.push($_) }); join "", @l.sort,@u.sort }";' file 

OR:

~$ raku -pe 's{ <?after \, > (\w+) } = "{ $0.comb.classify: { /<:Ll>/ ?? "lc" !! "uc" }, :into( my %case{Str} ); $_.join given %case.sort.map: *.value.sort.join }";' file 

Sample Output (2):

rap ,fglX MIT X11 rap ,flBPX 'MITER' rap ,fglB share git-grep rap ,bfl X11 rap ,flB xzfgrep rap ,fB X11 

Above uses the Unicode representation of lowercase letter, <:Ll> (see first link below for details). Also on display is Raku's ternary operator: Test ?? True !! False (see second link below for details). The two answers differ in that the first uses two arrays (directly) with a ternary, while the second uses a single hash (created via classify).

NOTE: Thanks to a comment by @StéphaneChazelas, it's probably better to use (<alpha>+) as the capture, instead of (\w+).

https://docs.raku.org/language/regexes#Predefined_character_classes
https://docs.raku.org/language/operators#infix_??_!!
https://docs.raku.org/routine/classify
https://docs.raku.org/language/regexes
https://raku.org

If we replace the comma in the input file with a dash, we can use getopts as usual to parse the rap function's options.

That change can be done with sed, and assuming we only ever need to change rap , at the start of any line to rap -, it would look like this:

sed 's/^rap ,/rap -/' file.in >file 

We would then be able to simply source the generated file in our script with . ./file assuming the rap function had been previously declared.

To parse the options in the rap function:

rap () { OPTIND=1 unset -v B_flag P_flag X_flag unset -v b_flag f_flag g_flag l_flag while getopts BPXbfgl opt; do case $opt in B) B_flag=true ;; P) P_flag=true ;; X) X_flag=true ;; b) b_flag=true ;; f) f_flag=true ;; g) g_flag=true ;; l) l_flag=true ;; *) echo 'Error' >&2; return 1 esac done shift "$(( OPTIND - 1 ))" # Act on set flags here. if "${f_flag-false}"; then echo 'The -f option was used' fi # The non-options are available in "$@". printf 'Other argument: %s\n' "$@" printf -- '---\n' } 

Note that by setting the flag variables in the while loop and acting on them after the loop, we avoid acting on duplicated options multiple times.