quotel.sh : quote lines using prefix and suffix strings. By default, those are double quotes.

quotel.sh

#!/usr/bin/env bash
#              bash 4.1.5(1)     Linux Ubuntu 10.04           Date : 2012-03-23
#
# _______________|  quotel : quote lines using prefix and suffix strings.
#
#           Usage:  quotel  [filename]  [prefix string]  [suffix string]
#                   #       stdin and double quotes are defaults.
#                   #       Use '~' to represent an empty string.
#
#    Dependencies:  sed


#  CHANGE LOG  LATEST version available:   https://bitbucket.org/rsvp/gists/src
#
#  2012-03-23  First version of a common idiom.


#           _____ PREAMBLE_v2: settings, variables, and error handling.
#
LC_ALL=POSIX
#      locale means "ASCII, US English, no special rules, 
#      output per ISO and RFC standards." 
#      Esp. use ASCII encoding for glob and sorting characters. 
shopt -s   extglob
#     ^set extended glob for pattern matching.
set -e
#   ^errors checked: immediate exit if a command has non-zero status. 
set -u
#   ^unassigned variables shall be errors.
#    Example of default VARIABLE ASSIGNMENT:  arg1=${1:-'foo'}

fname=${1:-'-'}
prefix=${2:-'"'}
suffix=${3:-'"'}


program=${0##*/}   #  similar to using basename
#  memf=$( mktemp /dev/shm/88_${program}_tmp.XXXXXXXXXX )

cleanup () {
     #  Delete temporary files, then optionally exit given status.
     local status=${1:-'0'}
     #  rm -f $memf
     [ $status = '-1' ] ||  exit $status      #  thus -1 prevents exit.
} #--------------------------------------------------------------------
warn () {
     #  Message with basename to stderr.          Usage: warn "message"
     echo -e "\n !!  ${program}: $1 "  >&2
} #--------------------------------------------------------------------
die () {
     #  Exit with status of most recent command or custom status, after
     #  cleanup and warn.      Usage: command || die "message" [status]
     local status=${2:-"$?"}
     cleanup -1  &&   warn "$1"  &&  exit $status
} #--------------------------------------------------------------------
trap "die 'SIG disruption, but cleanup finished.' 114" 1 2 3 15
#    Cleanup after INTERRUPT: 1=SIGHUP, 2=SIGINT, 3=SIGQUIT, 15=SIGTERM
#
# _______________     ::  BEGIN  Script ::::::::::::::::::::::::::::::::::::::::

#  If either prefix or suffix was an empty string '' 
#  our default variable assignment would be triggered, so...
if [ "$prefix" = '~' ] ; then
       prefix=''
fi

if [ "$suffix" = '~' ] ; then
       suffix=''
fi
#  ... we let ~ represent the empty string.
#      It cannot be used anyways due to the way we use sed below.


#  Take the whole line and substitute in prefix and suffix strings.
sed -e "s~^.*$~${prefix}&${suffix}~"  "$fname"  2> /dev/null   \
     ||  die "tilde ~ forbidden in prefix and suffix strings."  113


cleanup
# _______________ EOS ::  END of Script ::::::::::::::::::::::::::::::::::::::::

#  vim: set fileencoding=utf-8 ff=unix tw=78 ai syn=sh :