UNIX for Beginners Questions & Answers

[casupport@docvlapph005 ca]$ grep '^[s]' TheAgileApproach.dat | wc -l
0
[casupport@docvlapph005 ca]$ grep '^[S]' TheAgileApproach.dat | wc -l
1

[casupport@docvlapph005 ca]$ grep '^[s]' TheAgileApproach.dat
[casupport@docvlapph005 ca]$ grep '^[S]' TheAgileApproach.dat
String Filter increment. The most basic implementation that can be used for all data types is shown on the far left. Each version to the right of that adds more functionality.
[casupport@docvlapph005 ca]$

'^[s]'

grep -i -e"^s" -e" s" -o TheAgileApproach.dat|wc -l

$ cat TheAgileApproach.dat
String Filter increment. The most basic implementation that can be used for all data types is shown on the far left. Each version to the right of that adds more functionality.

$ grep -ie"^s" -e" s" -o TheAgileApproach.dat|wc -l
       2

[casupport@docvlapph005 ca]$ grep -i -e"^s" -e" s" -o TheAgileApproach.dat
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# Utility functions: print-as-echo, print-line-with-visual-space.
pe() { for _i;do printf "%s" "$_i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }

pl " Input data file $FILE:"
head $FILE

pl " Results:"
tr -s '[[:punct:][:space:]]' '\n' < $FILE |
tee t1 |
grep '^[sS]' |
tee t2 |
wc -l

pl  "Content of intermediate files (columnized by local utility):"
for f in t?
do
  pl " File: $f:"
  my-columns $f
done

pl " Results, considering "_" as a character:"
# tr -s '[^\w\s_]' '\n' < $FILE |
grep -o -P '[\w_]+' $FILE |
tee t1 |
grep '^[sS]' |
tee t2 |
wc -l

pl  "Content of intermediate files (columnized by local utility):"
for f in t?
do
  pl " File: $f:"
  my-columns $f
done

$ ./s1 data3

Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
OS, ker|rel, machine: Linux, 3.16.0-7-amd64, x86_64
Distribution        : Debian 8.11 (jessie) 
bash GNU bash 4.3.30
tr (GNU coreutils) 8.23
grep (GNU grep) 2.20

-----
 Input data file data3:
(2) SHALL we see?
(3) Is Sheriff Nokill allowing us to Shoot on Sight.
(4) We are agin "Shoot on site" but OK with "shoot on Sight".
(1) Nothing here to See, move along.
(0) Go USA! 
(1) un_Sharpened.
(1) un-Sharpened.
(1) Sharp
(13) total

-----
 Results:
13

-----
Content of intermediate files (columnized by local utility):

-----
 File: t1:
      see     Nokill   Shoot We    on   with  1       See   Go  Sharpened 1    
2     3       allowing on    are   site shoot Nothing move  USA 1         Sharp
SHALL Is      us       Sight agin  but  on    here    along 1   un        13   
we    Sheriff to       4     Shoot OK   Sight to      0     un  Sharpened total

-----
 File: t2:
SHALL Sheriff Sight site  Sight Sharpened Sharp
see   Shoot   Shoot shoot See   Sharpened

-----
 Results, considering _ as a character:
12

-----
Content of intermediate files (columnized by local utility):

-----
 File: t1:
2     Is       to    We    site  on      to    Go           un        total
SHALL Sheriff  Shoot are   but   Sight   See   USA          Sharpened
we    Nokill   on    agin  OK    1       move  1            1        
see   allowing Sight Shoot with  Nothing along un_Sharpened Sharp    
3     us       4     on    shoot here    0     1            13       

-----
 File: t2:
SHALL see Sheriff Shoot Sight Shoot site shoot Sight See Sharpened Sharp

grep -o "\b[sS][^ ]*" <<< "String Filter increment. The most basic implementation that can be used for all data types is shown on the far left. Each version to the right of that adds more functionality."
String
shown