Kinda silly at 143:
perl -pe's/(^|\s)((\d?\d)?(\d)(\d)\d{5}|(\d?\d)?(\d)(\d)\d\d|\d{1,3})(
+?=\s|$)/$1.($3?"    $3$4G":$4?"  $4.$5G":$6?" $6$7M":$7?" $7.$8M":$2)
+/ge'

[download]
but it does produce:
/dev/dsk/c0t1d0s1       1.2G    814M    391M    68%    /usr
/dev/dsk/c0t1d0s3       245M     44M    176M    21%    /var
/dev/dsk/c0t1d0s0       424M    187M    194M    49%    /home

[download]
from your sample (note truncation instead of rounding).
Maybe I can think of something more sensible in the morning.

upday:   Ok, this is simpler (102 chars):
perl -pe's/(^|\s)((\d*?)\d)(\d)\d\d(\d{3})?(?=\s)/$1.($5&&"   ").($3?"
+  $2":"$2.$4").($5?"G":"M")/sge'

[download]
It still preserves numeric alignment with the original text, eg,
$ echo \
1234 12 12345 123456 1234567 12345678 123456789 | perl -pe'. . .'
1.2M 12   12M   123M    1.2G      12G      123G

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and rounding adds 22 (to 124 chars):
perl -pe's/(^|\s)((\d*?)\d)(\d)(\d)\d(\d{3})?(?=\s)/$1.($6&&"   ").($3
+?"  ".($2+($4>4)):$2+($4+($5>4))/10).($6?"G":"M")/ges'

[download]
Update, the second:

Here's a funny format one at 79 chars:
perl -pe's/((\d*?)\d)(\d)\d\d(\d{3})? /$1.($2?"  ":".$3").($4?"   G ":
+"M ")/ge'

[download]
which produces this:
$ echo '
1234 12 123 12345 123456 7654321 12345678 123456789 ' | perl -pe'... 
1.2M 12 123 12  M 123  M 7.6   G 12     G 123     G

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And an extendible one at 114 chars (got to be ready for those terrabyte-sized disks):
perl -pe's!(^|\s)((\d*?)\d)(\d)\d\d((\d{3})*)(?=\s)!$"x($x=length$5).$
+1.($3?"  $2":"$2.$4").qw(K M G T)[$x/3]!ges'

[download]
Which does:
$ echo \
1234 1234567 123456789012 1234567890123 123456789012345 | perl ...
1.2K    1.2M         123G          1.2T            123T

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Ok, here's a real one at 117 chars that does 1024-type m's and g's and t's:
perl -pe's!\d{4,}(?=\s)!sprintf"   "x($x=(-4+length$&)/3).($x*3%3?"  %
+.0f":"%.1f").qw(M G T)[$x],$&/1024**int$x+1!ge'

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Which gets:
$ echo '
321 4321 654321 87654321 9876543210 98765432101 987654321012 '|perl...
321 4.2M   639M      84G       9.2T         92T         920T

[download]
This ignores several problems:  1) Before 5.6, perl expanded   `qw(...)' into   `split" ",'...'' (so you couldn't   [index]it );  2) There's no protection against filenames or whatever which end with a string of 4 digits;  and 3) There's no provision for catching a number at the end of the line.

Adding these back in, yields 132 chars:
perl -pe's!(^|\s)(\d{4,})(?=\s)!sprintf"$1%s".(($x=-4+length$2)%3?"  %
+.0f":"%.1f").(qw(M G T))[$x/=3],"   "x$x,$2/1024**int$x+1!ges'

[download]

(BTW, what comes after Terrabytes?)

Update the last:   Updated the above to save a few strokes (and round properly on the 1024 one (changed %d -> %.0f)).

  p

In reply to Re: A little golf anyone? by petral
in thread A little golf anyone? by deprecated

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