Shell script to read a character (upper or lower), digit, special symbol and display message according to the character entered
Posted in Decision Making
This script uses sed command to find out all digits or upper characters. -z string (conditional expression) will return true if the length of string is zero.
Script logic
Read one character
[1] Use sed command to determine input character is digit or not (sed -e 's/[A-Z]//g'))
[2] Attempt to match regex [0-9] i.e. all digit against the pattern space
[3] If successful, replace that portion matched with replacement // i.e. do nothing.
If digits are in input, it will replace all those digit, and if input is only digit, nothing is left i.e. string is zero and that is what tasted with -z conditional expression.
#!/bin/bash # Shell script to read a character (upper or lower), digit, special symbol and # display message according to the character entered # ----------------------------------------------- # Copyright (c) 2005 nixCraft project <http://cyberciti.biz/fb/> # This script is licensed under GNU GPL version 2.0 or above # ------------------------------------------------------------------------- # This script is part of nixCraft shell script collection (NSSC) # Visit http://bash.cyberciti.biz/ for more information. # ------------------------------------------------------------------------- char="" echo -n "Enter a one character : " read char # use sed command to determine input character is digit or not # -e : start script # s/[0-9]// : Attempt to match regex [0-9] i.e. all digit against the pattern space (echo $char). # If successful, replace that portion matched with replacement i.e. // do nothing. # g : Global replacement # so if digit are in input it will replace all those digit, and if input is only digit, nothing # is left i.e. string is zero and that is what tasted with -z if [ -z $(echo $char | sed -e 's/[0-9]//g') ] then echo "$char is Number/digit" elif [ -z $(echo $char | sed -e 's/[A-Z]//g') ] # find out if character is upper then echo "$char is UPPER character" elif [ -z $(echo $char | sed -e 's/[a-z]//g') ] # find out if character is lower then echo "$char is lower character" else echo "$char is Special symbol" # else it is special character fi
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Tags: conditional expression, conditional expressions, digits, elif, global replacement, if command, input character, pattern space, script logic, sed character is digit case, sed character is lower case, sed character is upper case, sed command ~ Last updated on: April 5, 2008
