Shell Programming and Scripting

#!/usr/bin/env bash

# @(#) s1       Demonstrate numbering lines matching regular expression, nl.

# Utility functions: print-as-echo, print-line-with-visual-space, debug.
# export PATH="/usr/local/bin:/usr/bin:/bin"
LC_ALL=C ; LANG=C ; export LC_ALL LANG
pe() { for _i;do printf "%s" "$_i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }
db() { ( printf " db, ";for _i;do printf "%s" "$_i";done;printf "\n" ) >&2 ; }
db() { : ; }
C=$HOME/bin/context && [ -f $C ] && $C nl

FILE=${1-data1}
E=expected-output.txt

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

pl " Expected output:"
cat $E

pl " Results:"
nl -bp"^[a-zA-Z]" -nln -s". " -w 1 $FILE

exit 0

$ ./s1

Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
OS, ker|rel, machine: Linux, 3.16.0-4-amd64, x86_64
Distribution        : Debian 8.4 (jessie) 
bash GNU bash 4.3.30
nl (GNU coreutils) 8.23

-----
 Input data file data1:
a(depends: )
bb(depends:lmbench )
cc(depends: )
    CONFIG_DEFAULT1=y
    CONFIG_IOSCHED1=y
    CONFIG_CGROUP1=y
ddd(depends: )
    CONFIG_GENERIC_CPU1=y
    CONFIG_CRYPTO_AES_NI1=m

-----
 Expected output:
1. a(depends: )
2. bb(depends:lmbench )
3. cc(depends: )
    CONFIG_DEFAULT1=y
    CONFIG_IOSCHED1=y
    CONFIG_CGROUP1=y

4. ddd(depends: )
    CONFIG_GENERIC_CPU1=y
    CONFIG_CRYPTO_AES_NI1=m

-----
 Results:
1. a(depends: )
2. bb(depends:lmbench )
3. cc(depends: )
       CONFIG_DEFAULT1=y
       CONFIG_IOSCHED1=y
       CONFIG_CGROUP1=y
4. ddd(depends: )
       CONFIG_GENERIC_CPU1=y
       CONFIG_CRYPTO_AES_NI1=m