Increment variable value by 1 shell programming

Question

I am a beginner to shell programming and it sounds like a very stupid question but i cant seem to be able to increase the variable value by 1  I have looked at tutorial but it only shows how to add together 2 variables  I have tried the following methods but it doesnt work  i 0   i  i 1   doesnt work   command not found  echo   i    i  expr  i 1    doesnt work   command not found  echo   i    i     doesnt work   command not found  echo   i    How do i increment the value of a variable by 1

User · Answer

There are more than one way to increment a variable in bash, but what you tried is not correct.

You can use for example arithmetic expansion:

i=$((i+1))

or only:

((i=i+1))

or:

((i+=1))

or even:

((i++))

Or you can use let:

let "i=i+1"

or only:

let "i+=1"

or even:

let "i++"

See also: http://tldp.org/LDP/abs/html/dblparens.html.

User · Answer

The way to use expr   i 0 i  expr  i   1    the way to use i      i      echo  i    Tested in gnu bash

User · Answer

you can use bc as it can also do floats  var   echo  1 2  bc

User · Answer

These are the methods I know   ichramm NOTPARALLEL    i 10  echo  i  10 ichramm NOTPARALLEL      i  1    echo  i  11 ichramm NOTPARALLEL      i i 1    echo  i  12 ichramm NOTPARALLEL    i  expr  i   1   echo  i  13   Note the spaces in the last example  also note that s the only one that uses  i

User · Answer

You can try this    i 0 i    i 1

[shell] Increment variable value by 1 ( shell programming)

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