Red Hat NETSCAPE MANAGEMENT SYSTEM 6.0 - CUSTOMIZATION User Manual download pdf (Page 275)

17.4 Identifying and Working with File Types 263

head <filename>

Head can be useful, but because it’s limited to the ﬁrst several lines, you won’t know how long the

ﬁle actually is. By default, you can only read the ﬁrst10linesofaﬁle, although we can specify the

numbertoseemorebytyping:

head -20 <filename>

Read head’s man page (man head) for more information. You’ll probably ﬁnd that less or more

are more helpful, because you can page through the ﬁle if you ﬁnd that the information you’re look-

ing for is further into the ﬁle than you originally thought.

The tail Command

The reverse of head (obviously), is tail.With(tail), you can review the last 10 lines of a ﬁle.

The cat Command

The command cat, short for concatenation, will dump the contents of the entire ﬁle on the screen.

Using cat can be handy if the ﬁle is fairly short, such as when we created sneakers.txt.Butifa

ﬁle is fairly long, it will easily scroll past you on the screen, since cat displays the whole ﬁle.

The grep Command

The grep command is pretty nifty for ﬁnding speciﬁc character strings in a ﬁle. Let’s say we want to

ﬁnd every reference we made to “coffee” in the ﬁle sneakers.txt, which we created in our login

directory. We could type:

grep coffee sneakers.txt

andwewouldseeeverylineinwhichtheword“coffee” could be found.

Tip: Unless otherwise speciﬁed, grep searches are case sensitive. That means that

searching for Coffee is different than searching for coffee.Soamonggrep’s options is -i,

which allows you to make a case-insensitive search through a ﬁle. Read the grep man

page for more about this command.

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Red Hat NETSCAPE MANAGEMENT SYSTEM 6.0 - CUSTOMIZATION User Manual Page 275