File input/output

• CHDIR - Change working directory
• GETCWD - Get current directory
• OPEN - Open file
• CLOSE - Close file
• STAT - Get file size
• TELL - Get current file position.
• SEEK - Find position in file
• READ - Read from file
• FGETS - Read line of text from file
• WRITE - Write to file
• SCAN - Read text item from file
• SCANEXP - Read text item from file
• SCANBIN - Read item from binary Bruker acqu file
• PRINT - Print and println
• PRINTF, FPRINTF, SPRINTF - Print formatted

NON-NMR specific filie input/output.

CHDIR - Change working directory

chdir <directory>

Change the current working directory to <directory>

Example:

chdir "/home/nmr/data"

GETCWD - Get current directory

<directory> = getcwd

Get the name of the current working directory.

Example:

%name = getcwd
println %name

OPEN - Open file

<file> = open <name>, <mode>

Open a general purpose file. <file> is the file handle, <name> is the filename and <mode> is the C-style open mode. If the file can not be opened, the file handle is set to 0.

Example 1:

        $newfile = open "myfile", "w"

Opens the new file "myfile" for writing, and

        $newfile = open "myfile", "r"

opens the same file for reading.

Example 2:

        $newfile = open "myfile", "r"
        @r = read $newfile    
        close $newfile

Read data from newfile into real array.

Example 3:

        %filename = "mydir/myfile"
        $newfile  = open %filename, "r"
        if $newfile == 0 then
            println "Error opening file " + %filename
            exit
        endif

Test if file is opened.

CLOSE - Close file

close <file>

Closes the file, thas was opened with the previous open command. <file> is the file handle of this file.

Example:

        close $newfile

STAT - Get file size

<size> = stat <filename>

Returns the file size in bytes. Returns -1 if file does not exist.

Example:

        $filesize = stat "myfile"
        println %filesize

TELL - Get current file position.

<position> = tell <file>

Get the current access position in the file.
 

SEEK - Find position in file

seek <file>, <position>

Set the access position in the file. <file> is the file handle and <position> is the new file position.

Example:

        seek $newfile, 0

positions the read/write position at the beginning of the file.

READ - Read from file

<array> = read <file> or <variable> = read <file>

Read data from <file> into <array> or into <variable>. The number of data read when <array> is used, is determined by the size of the array.

Example 1:

        @A[11..20] = read $filehandle

Reads 10 data elements into buffer A, stored at positions 11..20.

Example 2:

        @B = read $filehandle

Reads data into buffer B. The number of data is equal to the size of buffer B, which is can be accessed by the commands @#B or ?SI.

Example 3:

        $newnumber = read $filehandle

Read one element from <file> into newnumber.

FGETS - Read line of text from file

fgets ( <file> )

Read a line of text from a file, up to and including the '\n' character.  Similar to the C function with the same name.  Returns an empty string on error or end of file.
 

 Example:
 

$textfile = open "xx.au", "r"
do
    %line = fgets($textfile)
    print %line
while %line != ""
close $textfile

WRITE - Write to file

write <file>, <array> or  write <file>, <number>

Write data from <array> to <file> or write <number> to the file. The number of data written when <array> is used, is equal to the size of the array.

Example:

        write $filehandle, @c

Write all real and imaginary data to the file. The real data is stored before the imaginary data, and the number of data written is the size of @C * 2.

SCAN - Read text item from file

<value> = scan <file>, { <identifier string>, <line number>, } <identifier string>

Read one item (=text) from the text file <file> into the variable <value>. The <identifier string> is a text format string with one C-style scanf '%s'. If <line number> is defined, The first <identifier string> is first look for, and the second one is looked for <line number> lines below the first one.

Example:

        $file1 = open "data/1/acqu", "r"
        %sweep = scan file1, "##$SW_h= %s"
        close $file1
        println "SW = " + %sweep

SCANEXP - Read text item from file

<value> = scanexp <file>, { <format string>, <line number>, } <format string>

Read one item (=text) from the text file <file> into the variable <value>. The <identifier string> is a regular expression format string with one C-style scanf '%s'. If <line number> is defined, The first <identifier string> is first looked for, and the second one is looked for <line number> lines below the first one.

Regular Expressions:

The regular_expression defines the pattern to search for. The GREP-like wildcards include:

• x An ordinary character (not mentioned below) matches that character.
• \ The backslash quotes any character. "\$" matches a dollar-sign.
• ^ A circumflex at the beginning of an expression matches the beginning of a line.
• $ A dollar-sign at the end of an expression matches the end of a line.
• . A period matches any character except "new-line".
• : A colon matches a class of characters described by the following character.
• ":a" matches any alphabetic,
• ":d" matches digits,
• ":n" matches alphanumerics,
• ": " matches spaces, tabs, and other control characters, such as new-line.
• * An expression followed by an asterisk matches zero or more occurrances of that expression: "fo*" matches "f", "fo", "foo", etc.
• + An expression followed by a plus sign matches one or more occurrances of that expression: "fo+" matches "fo", etc.
• - An expression followed by a minus sign optionally matches the expression.
• [ ] A string enclosed in square brackets matches any character in that string, but no others. For example [bot] matches b, o, or t.
• [^] A circumflex at the start of the string in brackets means NOT. The expression matches any character except "new-line" and the characters in the string. For example, "[^xyz]" matches "abc" but not "axb".
• [-] A range of characters may be specified by two characters separated by "-". Note that, [a-z] matches alphabetics, while [z-a] never matches.

The concatenation of regular expressions is a regular expression.

Example:

        $file1 = open "data/procpar", "r"
        %sfd   = scanexp $file1, "^sfrq",  1, ":n %s"
        close $file1
        println "SF = " + %sfd

SCANBIN - Read item from binary Bruker acqu file

<value> = scanbin <file>, <identifier string>

Read one item (=text) from binary Bruker acqu file <file> into the variable <value>. The <identifier string> is a text string.

Example:

        $file1 = open "data/1/acqu", "r"
        # Test for binary file, first 4 bytes shoul be A000
        $test = read $file1
        if f2ascii($test) == "A000" then
            %sweep = scanbin $file1, "SW_h"
            println "SW = " + %sweep
        endif
        close $file1

PRINT - Print and println

print { <file> , } <string> or println { <file> , } <string>

The print command prints the string <string>, and println does the same and adds a newline. Without the <file> argument, print uses the current output stream. <file> can be a filehandle or the modifiers stdout or stderr, as in the C language.

Example 1:

        println "This is" + " an example"

Example 2:

        println stdout, "The value of var = " + %var

PRINTF, FPRINTF, SPRINTF - Print formatted

printf <fornat> , <arguments>
fprintf <file> , <fornat> , <arguments>
sprintf  ( <fornat> , <arguments> )

The printf command prints formatted output, much like in C.  The argument <format> is a C-type format string, and <arguments> is a list of numbers and strings, separated by comma's. However, the printf command is somewhat more flexible, as it can convert arguments that are of the wrong type. If there is not a sufficient number of arguments, the surplus of format specifies is skipped. The fprintf command is the same as the printf command, but prints its output to a file. Just as in C, sprintf prints to a string.

Example 1:
 

printf "Test %2.0f is %s\n", 12, "done"


Example 2:
 

printf "Use conversion: %d %f %s",  12, "12.5", 1.4e5


Example 3:
 

$newfile = open "myfile", "w"
fprintf $newfile, "Write to a file the character G: %c\n", "G"
close $newfile


Example 4:
 

%test = sprintf("Testing %4d %4d %4d", 1, 2, 3)