Passing tab char in command line

[alejandrina]

Hi all,

I want to pass a tab character as a command line parameter. Ihave this
statement to extract a char from the string:

char delim = args[0].charAt(0);

The problem is how do you write the command line? I've tried all of
these:

java testTab "\t"
java testTab "\\t"
java testTab \t
java testTab \\t
java testTab "\u0009"
java testTab \u0009

none work. "delim" above never gets the right character. Interestingly,
when I submit

java testTab "\u0009" or
java testTab "\\t"


args[0] contains a string of length = 2, the first character being "\"
and the second is the tab. Obviously, the parser feels the need to
"escape" my backslash character. How do you disable this behavior?

Thanks!

Alejandrina

 

[Oliver Wong]

Hi all,

I want to pass a tab character as a command line parameter. Ihave this
statement to extract a char from the string:

char delim = args[0].charAt(0);

The problem is how do you write the command line? I've tried all of
these:

java testTab "\t"
java testTab "\\t"
java testTab \t
java testTab \\t
java testTab "\u0009"
java testTab \u0009

none work. "delim" above never gets the right character. Interestingly,
when I submit

java testTab "\u0009" or
java testTab "\\t"


args[0] contains a string of length = 2, the first character being "\"
and the second is the tab. Obviously, the parser feels the need to
"escape" my backslash character. How do you disable this behavior?

When you type things "at the command line", you're actually giving input
to a program which is typically called a "shell". On Windows XP, for
example, most people use the shell known as "cmd.exe". On Linux, it might be
bash, or csh or some other shell.

Each shell has its own rules about what escaping and/or processing it
does on the input.

Obviously, the shell you're using chooses not to replace \t with a tab
character, though it does seem to be replacine two-character substring "\\"
with the single character substring "\".

Read the documentation for your shell to find out what escaping
facilities it provides, and how you can coax it into invoke the java program
with the tab as one of the parameters.

- Oliver

 

[Fred Kleinschmidt]

Hi all,

I want to pass a tab character as a command line parameter. Ihave this
statement to extract a char from the string:

char delim = args[0].charAt(0);

The problem is how do you write the command line? I've tried all of
these:

java testTab "\t"
java testTab "\\t"
java testTab \t
java testTab \\t
java testTab "\u0009"
java testTab \u0009

none work. "delim" above never gets the right character. Interestingly,
when I submit

java testTab "\u0009" or
java testTab "\\t"


args[0] contains a string of length = 2, the first character being "\"
and the second is the tab. Obviously, the parser feels the need to
"escape" my backslash character. How do you disable this behavior?

When you type things "at the command line", you're actually giving
input to a program which is typically called a "shell". On Windows XP, for
example, most people use the shell known as "cmd.exe". On Linux, it might
be bash, or csh or some other shell.

Each shell has its own rules about what escaping and/or processing it
does on the input.

Obviously, the shell you're using chooses not to replace \t with a tab
character, though it does seem to be replacine two-character substring
"\\" with the single character substring "\".

Read the documentation for your shell to find out what escaping
facilities it provides, and how you can coax it into invoke the java
program with the tab as one of the parameters.

- Oliver

And you might even try typing a double-quote,
followed by typing the tab key, and another double quote.

 

[Rhino]

Hi all,

I want to pass a tab character as a command line parameter. Ihave this
statement to extract a char from the string:

char delim = args[0].charAt(0);

The problem is how do you write the command line? I've tried all of
these:

java testTab "\t"
java testTab "\\t"
java testTab \t
java testTab \\t
java testTab "\u0009"
java testTab \u0009

none work. "delim" above never gets the right character. Interestingly,
when I submit

java testTab "\u0009" or
java testTab "\\t"


args[0] contains a string of length = 2, the first character being "\"
and the second is the tab. Obviously, the parser feels the need to
"escape" my backslash character. How do you disable this behavior?

Thanks!

Have you tried hitting the Tab key rather than typing backslashes and the
't' character?

 

[nkalagarla]

As Oliver mentioned the shell(cmd,sh,bash,ksh) is responsible for
escape processing of command line parameters. You could pass tab by
typing "(double quote) followed by tab key followed by "(double
quote).
In some shells(like cmd, bash) when you type TAB key they provide
command completion feature, if you type TAB once it fills with file
name. This should be disabled to pass just TAB character to the
application. For Windows, you could disable file and directory
completion by passing /F:OFF switch to cmd(cmd /F:OFF)or by updating
registry(more info at http://www.computerhope.com/cmd.htm).

-Rao

 

[Jeffrey Schwab]

Hi all,

I want to pass a tab character as a command line parameter. Ihave this
statement to extract a char from the string:

char delim = args[0].charAt(0);

The problem is how do you write the command line? I've tried all of
these:

java testTab "\t"
java testTab "\\t"
java testTab \t
java testTab \\t
java testTab "\u0009"
java testTab \u0009

none work. "delim" above never gets the right character. Interestingly,
when I submit

java testTab "\u0009" or
java testTab "\\t"


args[0] contains a string of length = 2, the first character being "\"
and the second is the tab. Obviously, the parser feels the need to
"escape" my backslash character. How do you disable this behavior?

<insert what everyone else said about shells />

If the shell doesn't do the kind of character substitution you want, the
testTab.main (should that be TestTab?) routine could check for sequences
like \t and interpret them itself.