I forgot the syntax and semantics for bash for
loop and tried to find the manual in the system. I couldn't find it. It wasn't in man bash
or man builtins
. Where can I do a quick local reference on bash
commands?

- 943
1 Answers
Maybe you want more details than from the man pages. Here are also some examples
From man bash
:
for name [ in word ] ; do list ; done
The list of words following in is expanded, generating a list of
items. The variable name is set to each element of this list in
turn, and list is executed each time. If the in word is omit‐
ted, the for command executes list once for each positional
parameter that is set (see PARAMETERS below). The return status
is the exit status of the last command that executes. If the
expansion of the items following in results in an empty list, no
commands are executed, and the return status is 0.
for (( expr1 ; expr2 ; expr3 )) ; do list ; done
First, the arithmetic expression expr1 is evaluated according to
the rules described below under ARITHMETIC EVALUATION. The
arithmetic expression expr2 is then evaluated repeatedly until
it evaluates to zero. Each time expr2 evaluates to a non-zero
value, list is executed and the arithmetic expression expr3 is
evaluated. If any expression is omitted, it behaves as if it
evaluates to 1. The return value is the exit status of the last
command in list that is executed, or false if any of the expres‐
sions is invalid.
Examples:
for i in *.txt;do echo textfiles: $i;done
for (( i=1; i<=20 ; i++ )) ; do echo $i;done
for i in .TXT;do mv $i ${i/.TXT/}.txt; done # "move .TXT *.txt"

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Doh! it was in
man bash
and I am not sure why I missed it. Yeah, the examples weren't present. – Senthil Kumaran May 29 '22 at 14:43 -
And what I missed was, adding a do statement after
;
while using for loop. – Senthil Kumaran May 29 '22 at 14:44 -
help for
give you what you want? See for example What is the help command? – steeldriver May 29 '22 at 14:09