Here the expression will be calculated by the program expr, which isn't a shell builtin but an external Unix program. So instead of simply adding 1 and s a program must be started und its output must be …

Aug 13, 2014 · Thus: expr 3 \* \( 2 + 1 \) Unless you're working on an antique unix system from the 1970s or 1980s, there is very little reason to use expr. In the old days, shells didn't have a built-in …

expr is an external program used by Bourne shell (i.e. sh). Bourne shell didn't originally have any mechanism to perform simple arithmetic. It uses expr external program with the help of backtick. The …

Nov 26, 2024 · 1 Expr is a command line tool, it is independent from the bash. It does not know anything about arrays. It gets command line arguments, exactly those what we refer as $1, $2, $3 etc in our …

Sep 1, 2025 · The man page has another note: The syntax of the expr command in general is historic and inconvenient. New applications are advised to use shell arithmetic rather than expr. And even if …

Apr 11, 2022 · For the first command, it seems expr found a match from the first character of abc and reports the matched length. But why does it produce 0 for the second command?

Dec 2, 2015 · Why did't the 'expr' give result for the second substring search. It can be seen that 'ab' had been prefixed to the substring in the third search. that is the only difference between 2nd and 3rd …

Dec 14, 2015 · I'm confused as to why this does not match: expr match Unauthenticated123 '^(Unauthenticated|Authenticated).*' it outputs 0.

The expr command can only do integer or string manipulations. Look at the man page for this guidance: Operands are either integers or strings. Integers consist of one or more decimal digits, with an …

Jul 31, 2016 · @Theophrastus: As suggested it works fine but what if i wanted to use expr instead of ( ()).