ksh 에서 문자열 핸들링하기

ksh는 아주 기본적인 쉘이어서 라이브러리는 커녕
기본적인 스트링 함수조차 찾기 어렵다.

제한적인 기능 속에서도 도움이 되는


The pattern in the following uses the same wildcards as for filename matching.

${#var}
    $var의 길이를 리턴
${var%pattern}
    removes the shortest suffix of $var patching pattern
${var%%pattern}
    removes the longest suffix of $var patching pattern
${var#pattern}
    removes the shortest prefix of $var patching pattern
${var##pattern}
    removes the longest prefix of $var patching pattern

Numeric variables

$(( integer expression ))
    The $(( ... )) construction interprets the contents as an arithmetic expression (integer only). Variables are referenced by name without the "$". Most of the arithmetic syntax of the 'C' language is supported, including bit manipulations (*,/,+,-,|,&,<<,>>. Use parentheses for changing precedence).

Examples
datapath=/data/public/project/trials/set1/datafile.dat

filename=${datapath##*/}
    filename is set to "datafile.dat" since the longest prefix pattern matching "*/" is the leading directory path (compare basename)
path=${datapath%/*}
    path is set to "/data/public/project/trials/set1" since the shortest suffix pattern matching "/*" is the filename in the last directory (compare dirname)

i=$((i+1))
    often used in while loops