Practical Programming in Tcl & Tk, Third Edition

File Attributes

There are several file operations that return specific file attributes: atime, executable, exists, isdirectory, isfile, mtime, owned, readable, readlink, size and type. Refer to Table 9-2 on page 102 for their function. The following command uses file mtime to compare the modify times of two files. If you have ever resorted to piping the results of ls -l into awk in order to derive this information in other shell scripts, you will appreciate this example:

Example 9-2 Comparing file modify times.

proc newer { file1 file2 } { if ![file exists $file2] { return 1 } else { # Assume file1 exists expr [file mtime $file1] > [file mtime $file2] } }

The stat and lstat operations return a collection of file attributes. They take a third ...