Print the first or last lines of a file, follow changes, and optionally filter the output, replacing or highlighting text parts with a free open source command line tool for Windows, Mac OS X and Linux.
sfk tail [-lines=n] [-f[ollow] [filename]sfk ... +[t]tail [-lines=n]
1. print last lines of a file, optionally following changes.
to use file content processing, provide a single filename.
2. print last text lines procuded by a previous command.
to process chain text ttail is recommended.
-lines=n print last n lines (default is 10).
-follow or -f waits for file changes, printing them endlessly.
if file is recreated or shrunk, rereads the last lines.
to post-process tail output, e.g. with +filter, always
add +loop at the end of the command sequence.
-nowait if tail is reached multiple times in a chain by +loop
then do not wait for a file size change but force
stepping of the command chain.
-quiet do not tell verbosely about read restarts.
-polltime=n with -follow, specifies the delay in milliseconds before
the file is checked again for changes. default is 500.
-altsize use a different method to determine the file size
(stat instead of seek). may help if the default method
fails to read the file, or to improve performance.
-verbose tell in detail what is done.
see alsosfk filter -tail=n read and search last n lines of text files.
sfk view GUI tool to view all text files of a folder, then jump
through file ends by ctrl+end.
web referencehttp://stahlworks.com/sfk-tailexamplessfk tail -follow logs\access.log
immediately lists last lines, then all added lines over time.
sfk tail -f c:\temp\log.txt +filter -+error: -+warning: +loop
endless filter of error and warning messages from log.txt.
example sfk script with conditional executionfile logfilter.txt:sfk label checklog
+tail -follow logfile.txt
+tee toterm +storetext
+filter -+error: -justrc
+if "rc>0" call myalert
+gettext +filter -+alldone: -justrc
+if "rc>0" stop
sfk label myalert
+then run -yes "myalert.bat" +end
sfk script logfilter.txt
will run myalert.bat whenever errors appear in logfile.txt.
the script stops as soon as "alldone" appears in the log.
to allow double filtering of the chain text it must be
stored before the first filter, then restored.
if you want to both tail and filter on several phrases,
the command may become hard to read and to edit. as an
alternative, you may put it into a batch embedded sfk script,
e.g. under windows, create a file
sfk script filtlog.bat -from begin
sfk label begin
+tail -f log.txt
-high red error:*
-high yellow warning:*
-high blue debug:*
then type "filtlog". creating command sequences this way
allows better readability, and easy editing in any editor.
see alsosfk filter - all options for selection and post-processing of text
sfk partcopy - copy byte block from the beginning of a file
sfk script - how to create script files with sfk commands
sfk samp - ready-to-use templates for windows and linux scripts