Designing Program Output

Variable Attributes(typeset)

typse -L10 var_name

or

typeset -L10 var_name="value string"

Attribute/typeset option/sample

Left Justify    -L       "string    "
Right Justify  -R       "    string"
Lower Case   -l        "string"
Upper Case   -u       "STRING"

Display Formatted Data

Formatted:    print   "$var"
Unformatted: print    $var
Conversion:   printf  "%.10s"  "$var"      //built-in cmd인 print와 다르게 external cmd인 printf는 c언어의 printf와 같다. man printf 커맨드로 메뉴얼 페이지에서 확인

#! Formatted, Unformatted의 예..

$ var='this is a test string'
$ print $var
this is a test string
$ print "$var"
this is a test string
$ var='this           is     a   test        string'
$ print $var
this is a test string                             //여러 공백들이 하나로 대체된다.
$ print "$var"
this           is     a   test        string      //의도한 string이 출력된다
$ cp file1                           file2         //shell은 공백의 중복을 하나의 공백으로 대체하므로 이러한 명령도 의도대로 잘 사용된다. 물론 의도한 공백을 넣은 string을 출력할 땐 

#! printf의 예...

#!/usr/bin/sh
# printf.sh
# conversion at output time

var="posix shell programming"
# notice, printf does not produce an automatic linefeed

printf "%.5s" "$var"
# output is converted to a 5 character string
# output: "posix"$

printf "%30s"  "$var"
# output is extended to right justified 30 char string
# no linefeed before the next shell prompt '$'
# output: "posix shell programming       "$
printf "%-30s"  "$var"
# output is extended to left justified 30 char string
# output: "       posix shell programming"$

printf "\n%.11s\n" "$var"
# output is trimmed to 11 characters, linefeed added

printf "Interpreter:%11s\n" "$var"
# output includes some added text, then 11 characters

exit

UNIX Command Reference Section 

알아도 한 번 더 보고 갈만큼 유용

cut   : Extract data

grep : Search/extract

tail   : Show last n lines

wc   : General counter

sort  : Sorts data

tr     : Translate/Squees;Change old to new

pr    : Print files

!! 아래는 처음보지만 흥미로운 기능

tput 

cursor 이동, 텍스트 줄긋기, 드래그 한 것 처럼 하이라이팅 할 때, 로그인 페이지에서 비밀번호 칠 때처럼 글자 안보이게 입력하기(echo 해제) 등과 같은 기능들을 수행할 수 있다.

Command to enable/disable the capnames

Cursor Positioning

one common capnames to control the cursor position

home : Moves cursor to the top left corner of the screen (home position)

cup x y : Sets cursor position; needs ros (x) and column (y) down from the home position

cuu1, cud1, cub1, cuf1 : Sets cursor {up, down, left, forward} one line

Some useful shell variables

COLUMNS : Sets the number of columns in the current window

LINES : Sets the number of rows in the current window

 $ cat middle.sh

#!/usr/bin/sh

        # middle.sh

        # print in the middle of the window

        # use an alias to save typing later

        alias go="tput cup"

        back="$(tput cub1)"

        tput clear

        # find the middle of the screen (bc is a calculator tool)

        mid_col="$(print $COLUMNS/2 | bc)"

        mid_row="$(print $LINES/2 | bc)"

        # position the cursor in the middle of the screen

        go $mid_row $mid_col

        # backup half the width of the text string

        print -n "${back}${back}${back}"

        print -n "MIDDLE"

        # move to the last line in the window

        go $LINES 1

        exit