The idea of adding a shell script from 1 to 100

First, use double brackets (()) to calculate

#!/bin/bash#a=0for ((b=0; b<=; b++));  Do     ((a=a+b))                                // can also be written as a=$ ((a+b))  Done Echo $a

Second, seq, tr, sed, BC together to complete the calculation method

seq | TR ' \ n ' ' + '| sed ' s/\+$/\n/ '|BC      //seq 100 will be from 1 to

Iii. combined use of For statement, SEQ, let

#!/bin/bash#a=1 for in 'seq2';  Do Let a= $a + $b                                 //letbehind the variable, do not add the $ symbol will not be error- doneecho $a

Iv. combined use of the For statement, double brackets, expr

#!/bin/bash#a=0for ((b=0; b<=; b++));  Do     a= 'expr $a + $b '                        // a space must be left before and after the + sign in the following expr command  Done Echo $a

The idea of adding a shell script from 1 to 100