Bourne Shell: Difference between revisions

A Bourne Shell script begins with a [[wp:shebang (Unix)|shebang]] (also known as a ''hashbang'') like this, which tells the operating system to use the Bourne compatible shell interpreter:

 

 

In 2009, ''[[wp:Computerworld|Computerworld]]'' published an in-depth interview with Steve Bourne, "[https://web.archive.org/web/20100212210742/computerworld.com.au/article/279011/a-z_programming_languages_bourne_shell_sh/ The A-Z of Programming Languages: Bourne shell, or sh]", which details the Bourne shell origins and design decisions.

Bourne Shell and Heirloom Shell have problems with here documents. Here is one such problem. A substitution, inside a here document, inside backquotes, inside double quotes, does insert too many backslashes.

 

cat <<!

here $1

expr "`f string`"

# Output from Bourne Shell: here \s\t\r\i\n\g

 

The workaround is to move the backquotes to an assignment.

 

cat <<!

here $1

var=`f string`

expr "$var"