strings in bash

Hi I need to go over characters in string in bash including spaces. How can I d开发者_运维技巧o it?

Bash does support substrings directly (If that's what the OP wants):

$ A='Hello World!'
$ echo "${A:3:5}"
lo Wo
$ echo "${A:5:3}"
 Wo
$ echo "${A:7:3}"
orl

The expansion used is generalized as:

${PARAMETER:OFFSET:LENGTH}

PARAMETER is your variable name. OFFSET and LENGTH are numeric expressions as used by `let'. See the bash info page on shell parameter expansion for more information, since there are a few important details on this.

Therefore, if you want to e.g. print all the characters in the contents of a variable each on its own line you could do something like this:

$ for ((i=0; i<${#A}; i++)); do echo ${A:i:1}; done

The advantage of this method is that you don't have to store the string elsewhere, mangle its contents or use external utilities with process substitution.

Not sure what you really mean, but in almost all cases, problems with strings including spaces can be solved by quoting them.

So, if you've got a nice day, try "a nice day" or 'a nice day'.

You use some external tool for it. The bash shell is really meant to be used to glue other programs together in usually simple combinations.

Depending on what you need, you might use cut, awk, sed or even perl.

Try this

#/bin/bash

str="so long and thanks for all the fish"
while [ -n "$str" ]
        do
                printf "%c\n" "$str"
                str=${str#?}
done