[Article
27.12
gave a sense of how easy it might be to write custom search programs
in Perl...but until you learn the language, you can't rip these off
whenever you find yourself in need. This article describes a few
more custom greps written in Perl. It doesn't show the scripts
themselves, just how to use them. If you like them, they are on the
disc and the online archive. -TOR ]
tgrep
| The tgrep program greps only those files containing textual
data. It's useful in a directory that has mixed binary and textual
files, when the filenames aren't a sufficient clue to the nature of the
file. tgrep has one option, -l, which causes it to list
the files containing the pattern rather than listing the lines
containing the pattern. |
|---|
pipegrep
| The pipegrep program greps the output of a series of commands.
The difficulty with doing this using the normal grep program is
that you lose track of which file was being processed. This program
prints out the command it was executing at the time, including the
filename. The command, which is a single argument, will be executed
once for each file in the list. If you give the string {}
anywhere in the command, the filename will be substituted at that
point. Otherwise the filename will be added on to
the end of the
command. This program has one option, -l, which causes it to
list the files containing the pattern.
For example [nm is a programmers' utility that prints symbol name
lists-JP ]: |
|---|
$ cd /usr/lib
$ pipegrep 'sys_nerr' nm lib*.a
nm /usr/lib/libX11.a |: U _sys_nerr
nm /usr/lib/libXaw.a |: U _sys_nerr
nm /usr/lib/libXaw.a |: U _sys_nerr
nm /usr/lib/libc.a |: U _sys_nerr
.
.
.
cgrep
| The cgrep program greps for a pattern in the specified files, and
prints out that line with several lines of surrounding context.
This context grep script
lets you specify how many lines of context you want if you
want more or less than the default. For example: |
|---|
$ cgrep -3 pattern files
would give you three lines of context above and below the matching
line. Each occurrence is separated from the next by a short
horizontal line (-----).
- LW, RS, TC from O'Reilly & Associates' Programming Perl
