Silas Sewell - String http://www.silassewell.com/blog/tag/string Infrastructure Development Sat, 08 Jan 2011 00:00:00 GMT http://www.silassewell.com/ en hourly 1 String Slicing in Bash (like Python) http://www.silassewell.com/blog/2009/03/12/string-slicing-in-bash-like-python/ Thu, 12 Mar 2009 00:00:00 GMT silas http://www.silassewell.com/blog/2009/03/12/string-slicing-in-bash-like-python/ A simple function to slice strings in Bash similar to Python's string slicing functionality.

Examples

[silas@pluto ~]$ string_slice "12345" 0 1
1
[silas@pluto ~]$ string_slice "12345" 0 3
123
[silas@pluto ~]$ string_slice "12345" 2 3
3
[silas@pluto ~]$ string_slice "12345" 2 -2
3
[silas@pluto ~]$ string_slice "12345" -3
345

Implementation

function string_slice {
    STRING="$1"
    declare -i LENGTH="${#STRING}"
    declare -i START="$2"
    declare -i END="$3"
    if [ $START -lt 0 ]; then
        START=$[ $LENGTH + $START ]
    fi
    if [ $END -le 0 ]; then
        END=$[ $LENGTH + $END ]
    fi
    START=$[ $START + 1 ]
    (echo "$STRING" | cut -c $START-$END) 2> /dev/null
}
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