Linux Shell reads a line

Linux Shell reads a line

Method One

By specifying IFS--Internal Field Separator , by IFS default <space><tab><newline> , you can set a value in the script IFS

DEMO 1

$cat t1.txt abcfd   $cat test_IFS.sh #! /bin/shIFS="c"for LINE in `cat t1.txt`do     echo $LINEdone$sh test_IFS.sh abfd

You need to read a line here just to IFS="\n" set the line break.

DEMO2

$cat t1.txt a bc d

Not setIFS

$ cat test_IFS.sh #! /bin/sh#IFS="\n"for LINE in `cat t1.txt`do    echo $LINEdone$sh test_IFS.sh abcd

Set upIFS="\n"

$ cat test_IFS.sh #! /bin/shIFS="\n"for LINE in `cat t1.txt`do    echo $LINEdone$sh test_IFS.sh a bc d

This will allow you to read a line.

Method 2

Use the read command to read a line from the standard input, based on the IFS partitioning and assign the corresponding variable, here for our intentional IFS set to, for the & demonstration

DEMO3

$cat test_read.sh #! /bin/shIFS="&"printf "Enter your name, rank, serial num:"read name rank sernoprintf "name=%s\nrank=%s\nserial num=%s" $name $rank $serno $sh test_read.sh Enter your name, rank, serial num:zk&1&123name=zkrank=1serial num=123

So we know that read every time we read a line, it's okay to use the read command.

DEMO4

$cat readline_1.sh #! /bin/shcat t1.txt | while read LINEdo    echo $LINEdone$sh readline_1.sh a bc d

Here is a file redirection to read processing

Method 3

Use read to read file redirection

DEMO5

$cat readline_2.sh #! /bin/shwhile read LINEdo    echo $LINEdone < t1.txt$sh readline_2.sh a bc d

Recommended method of Use 3