Bash 下如何逐行讀取一個文件

圖01：Bash 腳本：讀取文件並逐行輸出文件

Bash 腳本：逐行讀取文本文件並創建為 pdf 文件

我的輸入文件如下（faq.txt）:

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我的 bash 腳本:

#!/bin/bash
# Usage: Create pdf files from input (wrapper script)
# Author: Vivek Gite <Www.cyberciti.biz> under GPL v2.x+
#------------------------------------------------------
#Input file
_db="/tmp/wordpress/faq.txt"

#Output location
o="/var/www/prviate/pdf/faq"

_writer="~/bin/py/pdfwriter.py"

# If file exists 
if [[ -f "$_db" ]]
then
    # read it
    while IFS=&apos;|&apos; read -r pdfid pdfurl pdftitle
    do
        local pdf="$o/$pdfid.pdf"
        echo "Creating $pdf file ..."
    #Genrate pdf file
        $_writer --quiet --footer-spacing 2 
        --footer-left "nixCraft is GIT UL++++ W+++ C++++ M+ e+++ d-" 
        --footer-right "Page [page] of [toPage]" --footer-line 
        --footer-font-size 7 --print-media-type "$pdfurl" "$pdf"
    done <"$_db"
fi

技巧：從 bash 變數中讀取

讓我們看看如何在 Debian 或者 Ubuntu Linux 下列出所有安裝過的 php 包，請輸入：

# 我將輸出內容賦值到一個變數名為 $list中 #

list=$(dpkg --list php* | awk '/ii/{print $2}')
printf '%sn' "$list"

示例輸出:

php-pear
php5-cli
php5-common
php5-fpm
php5-gd
php5-json
php5-memcache
php5-mysql
php5-readline
php5-suhosin-extension

你現在可以從 $list 中看到它們，並安裝這些包：

#!/bin/bash
# BASH can iterate over $list variable using a "here string" #
while IFS= read -r pkg
do
    printf 'Installing php package %s...n' "$pkg"
    /usr/bin/apt-get -qq install $pkg
done <<< "$list"
printf &apos;*** Do not forget to run php5enmod and restart the server (httpd or php5-fpm) ***n&apos;

示例輸出:

Installing php package php-pear...
Installing php package php5-cli...
Installing php package php5-common...
Installing php package php5-fpm...
Installing php package php5-gd...
Installing php package php5-json...
Installing php package php5-memcache...
Installing php package php5-mysql...
Installing php package php5-readline...
Installing php package php5-suhosin-extension...

*** Do not forget to run php5enmod and restart the server (httpd or php5-fpm) ***

via: http://www.cyberciti.biz/faq/unix-howto-read-line-by-line-from-file/

作者： VIVEK GIT 譯者：strugglingyouth 校對：wxy

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本文轉載來自 Linux 中國: https://github.com/Linux-CN/archive