Linux基础教程Shell脚本编程.ppt

/faq/bash-for-loop/ * #!/bin/bash # filename: change_file_SUFFIX.sh # 将当前目录下所有以（$1）为后缀的文件改为以（$2）为后缀的文件 if [ $# -eq 2 ]; then for f in *.$1; do mv $f `basename $f .$1`.$2; done else echo Usage: $0 echo Exmaple: $0 txt doc fi * /faq/bash-while-loop/ * /file-management/read-a-file-line-by-line/ #!/bin/bash # Shell script utility to read a file line line. # Once line is read it can be process in processLine function # You can call script as follows, to read myfile.txt: # ./readline myfile.txt # Following example will read line from standard input device aka keyboard: # ./readline # ----------------------------------------------- # Copyright c 2005 nixCraft /fb/ # This script is licensed under GNU GPL version 2.0 or above # ------------------------------------------------------------------------- # This script is part of nixCraft shell script collection NSSC # Visit / for more information. # ------------------------------------------------------------------------- # User define Function UDF processLine line $@ # get all args # just echo them, but you may need to customize it according to your need # for example, F1 will store first field of $line, see readline2 script # for more examples # F1 $ echo $line | awk print $1 echo $line ### Main script stars here ### # Store file name FILE # Make sure we get file name as command line argument # Else read it from standard input device if [ $1 ]; then FILE /dev/stdin else FILE $1 # make sure file exist and readable if [ ! -f $FILE ]; then echo $FILE : does not exists exit 1 elif [ ! -r $FILE ]; then echo $FILE: can not read exit 2 fi fi # read $FILE using the file descriptors # Set loop separator to end of line BAKIFS $IFS IFS $ echo -en \n\b exec 3 0 exec 0 $FILE while read -r line do # use $line variable to process line in processLine function processLine $line done exec 0 3 # restore $IFS which was used to determine what the field separators