網路管理語言 Perl 入門與實作: | ||
---|---|---|
<<< Previous | 3. Perl 簡介 | Next >>> |
除了用前一節的方式執行 Perl script 之外,還可以利用 Perl 的命令列選項:
[ols3@p4 sample]$ perl -e 'print "Hello Perl !!\n";' Hello Perl !! |
這種方式,主要是利用 -e 選項,將欲執行的述敘放在 '' 單引號之間。
比如,以下方法可以去掉文件中的 ^M 符號:
perl -pi.bak -e 's/\r//g;' index.html |
^M 符號的產生,大多是由於 Windows 平台的文件,在上傳檔案至 Linux/Unix平台的過程中,其換行符號沒有做適當的轉換所致。
以下這個命令列選項可以得知 Perl 的版本代碼:
perl -v 結果: This is perl, v5.8.0 built for i386-linux-thread-multi Copyright 1987-2002, Larry Wall Perl may be copied only under the terms of either the Artistic License or the GNU General Public License, which may be found in the Perl 5 source kit. Complete documentation for Perl, including FAQ lists, should be found on this system using `man perl' or `perldoc perl'. If you have access to the Internet, point your browser at http://www.perl.com/, the Perl Home Page. |
由上可知,所用的 Perl 版本是 5.8.0
至於 perl -c 這個選項,在前一節中已提到,可用來檢查 Perl script 語法的正確性:
[ols3@p4 sample]$ perl -c hello.pl hello.pl syntax OK |
Perl 還有非常多的命令列選項,欲知詳情,請下:
[ols3@p4 perl_intro]$ perl -h Usage: perl [switches] [--] [programfile] [arguments] -0[octal] specify record separator (\0, if no argument) -a autosplit mode with -n or -p (splits $_ into @F) -C enable native wide character system interfaces -c check syntax only (runs BEGIN and CHECK blocks) -d[:debugger] run program under debugger -D[number/list] set debugging flags (argument is a bit mask or alphabets) -e 'command' one line of program (several -e's allowed, omit programfile) -F/pattern/ split() pattern for -a switch (//'s are optional) -i[extension] edit <> files in place (makes backup if extension supplied) -Idirectory specify @INC/#include directory (several -I's allowed) -l[octal] enable line ending processing, specifies line terminator -[mM][-]module execute `use/no module...' before executing program -n assume 'while (<>) { ... }' loop around program -p assume loop like -n but print line also, like sed -P run program through C preprocessor before compilation -s enable rudimentary parsing for switches after programfile -S look for programfile using PATH environment variable -T enable tainting checks -t enable tainting warnings -u dump core after parsing program -U allow unsafe operations -v print version, subversion (includes VERY IMPORTANT perl info) -V[:variable] print configuration summary (or a single Config.pm variable) -w enable many useful warnings (RECOMMENDED) -W enable all warnings -X disable all warnings -x[directory] strip off text before #!perl line and perhaps cd to director |
除了 -e -c -v -h 之外,上述選項中比較常用的還有 -w (打開警告訊息) -T (安全檢查),往後我們會再加以說明。
<<< Previous | Home | Next >>> |
3.2 Hello Perl! | Up | 3.4 習題 |