bash - What does < in Shell Scripts do? -

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• what symbols -, < , > mean? 1 answer

for example,

matlab -nodesktop -singlecompthread < run%d/run.m 

i know means matlab suppose use run.m file in run%d directory mean shells in general?

by itself, command < filename tells shell run named command input coming file filename, instead of terminal typed command line.

you can go other way, too, sending output of command file, command > filename.

there 2 different output streams connected terminal - normal one, called "standard output" , redirected >, , "standard error" stream, lets program tell when went wrong though normal output going file instead of terminal. if don't want see error messages, want them go terminal well, can use >& filename.

if want send errors own separate file, can use 2>*error_filename*; leaves standard output stream alone, going terminal or wherever sent > or |.

there's lot more can do, use output of 1 command file anywhere command expects filename. see the link konsolebox posted more details.