Shell ${} and #,% Usage

lufy

May 02, 2018

In shell scripts, symbols are very usefull to handle strings in variables. Next list some frequently used methods of getting specified strings from variables.
${var##*str}&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;get string after the last str in $var
${var#*str}&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;get string after the 1st str in $var
${var%%str*}&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; get string before the 1st str in $var
${var%str*}&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;get string before the last str in $var
${#var}&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;get how many bytes in $var.
E.g.
var=abcddcba
echo ${var##*c}&nbsp; &nbsp; &nbsp; &nbsp; get "ba"
echo ${var#*c}&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; get "ddcba"
echo ${var%%c*}&nbsp;&nbsp; &nbsp; &nbsp; &nbsp;get "ab"
echo ${var%c*}&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; get "abcdd"
echo ${#var}&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;get "8"

Shell ${} and #,% Usage

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