Login or Register to Ask a Question and Join Our Community


Shell Programming and Scripting

Equivalent to let command in POSIX shell

Login to Discuss or Reply to this Discussion in Our Community

 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting Equivalent to let command in POSIX shell
# 1  
Old 02-06-2019
Equivalent to let command in POSIX shell
Hi all,

I am learning POSIX shell programming, and the book I read, uses the let command for integer arithmetic.

I have downloaded and use the shellcheck program on Linux.

This programs says:

Code:
In POSIX sh, 'let' is undefined.


See the screenshot attached.


What is the POSIX equivalent of let, for doing arithmetic operations, like:

Code:
let "x=x+5"

Thank you a lot.
Moderator's Comments:
Mod Comment Please use CODE tags (not QUOTE tags) when displaying sample output. Also use CODE tags when displaying sample input and when displaying code segments.
Equivalent to let command in POSIX shell-shellcheckpng
Last edited by Don Cragun; 02-06-2019 at 08:34 PM..
# 2  
Old 02-06-2019
The POSIX equivalent is:
Code:
x=$((x+5))

These 4 Users Gave Thanks to Don Cragun For This Post:
dodona johnprogrammer Neo PLANTROON
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. OS X (Apple)

Generate a random number in a fully POSIX compliant shell, 'dash'...

Hi all... Apologies for any typos, etc... This took a while but it didn't beat me... Although there are many methods of generating random numbers in a POSIX shell this uses integer maths and a simple C source to create an executable to get epoch to microseconds accuracy if it is needed. I take... (8 Replies)
Discussion started by: wisecracker
8 Replies

2. Shell Programming and Scripting

Q: Is SQRT(n) possible in a POSIX compliant shell? A: Yes within limits.

Hi all... This is just a fun project to see if it is possible to get a square root of a positive integer from 1 to 9200000 to 6 decimal places on a 64 bit architecture machine. It is coded around dash and the results show the values from 0 to 10000. Complex numbers can easily be catered for by... (3 Replies)
Discussion started by: wisecracker
3 Replies

3. What is on Your Mind?

Popularity-Boost for the POSIX-Shell in the Era of Containerized Computing?

Not even thinking that POSIX-Shell is deprecated, but I like working with bash very much, because of it's increased comfort and advanced functions. And in my world here it's available everywhere as default. Working with kubernetes now, it seems there is a paradigm shift in terms of resources.... (1 Reply)
Discussion started by: stomp
1 Replies

4. Shell Programming and Scripting

Pure POSIX shell scripting...

Hi all... This is more of a concensus question than help... As many of you know I am experimenting with the limitations of Pure POSIX shell scripting. Q: Is the directory /bin considered part of the Pure POSIX shell or must I stick entirely with the builtins only? The reason is I... (2 Replies)
Discussion started by: wisecracker
2 Replies

5. Shell Programming and Scripting

Is Rule 7 of POSIX shell grammar rules written correctly?

The POSIX shell standard grammar rules are at Shell Command Language I am trying to understand Rule 7 and I don't. I think there may be some mistakes there. I am not complaining about the standard; rather, I am concerned that my perception is wrong, and I don't understand something important.... (3 Replies)
Discussion started by: Mark_Galeck
3 Replies

6. UNIX for Dummies Questions & Answers

Create the equivalent of the command WC

hi all, i'm trying to do this exercise, i want to create a script that can substitute WC command in unix, can someone help me? (11 Replies)
Discussion started by: Marina2013
11 Replies

7. Shell Programming and Scripting

Logical expression in POSIX compliant Korn Shell

Hi, i want to check if a variable var1 is not a or b or c pseudo code: If NOT (var1 = a or var1 = b or var1 = c) then ... fi I want to use POSIX complaint Korn shell, and for string comparison For the following code, logical.sh #!/usr/bin/ksh var="j" echo "Var : $var" if ! { || ||... (12 Replies)
Discussion started by: ysrini
12 Replies

8. AIX

smitty equivalent command line command

i know after you do something in smitty via the gui, you can click something in smitty that will show you how to do the same thing via the command line, (not using the gui) can anyone tell me how (2 Replies)
Discussion started by: asyed123
2 Replies

9. UNIX for Advanced & Expert Users

Need svcs equivalent command

Hi, I am new to HP-UX. Can someboby help me with the svcs equivalent command in HP-UX ??? svcs is command that we use in Solaris for service status. I need to get the status of services in HP-UX. Thanks in advance. (2 Replies)
Discussion started by: EmbedUX
2 Replies

10. Shell Programming and Scripting

Windows command shell equivalent in Unix

In Windows we use cmd.exe \c as the command SHell What is its equivalent in UNIX ? Thanx for all your help. (10 Replies)
Discussion started by: simonsimon
10 Replies
Login or Register to Ask a Question