Split string using \r\n using IFS in bash

问题

I would like to split string contains \r\n in bash but carriage return and \n gives issue. Can anyone give me hint for different IFS? I tried IFS=' |\' too.

input:

projects.google.tests.inbox.document_01\r\nprojects.google.tests.inbox.document_02\r\nprojects.google.tests.inbox.global_02

Code:

IFS=$'\r'
inputData="projects.google.tests.inbox.document_01\r\nprojects.google.tests.inbox.document_02\r\nprojects.google.tests.inbox.global_02"
for line1 in ${inputData}; do
    line2=`echo "${line1}"`
    echo ${line2} //Expected one by one entry
done

Expected:

projects.google.tests.inbox.document_01
projects.google.tests.inbox.document_02
projects.google.tests.inbox.global_02

回答1:

Following awk could help you in your question.

awk '{gsub(/\\r\\n/,RS)} 1'  Input_file

OR

echo "$var" | awk '{gsub(/\\r\\n/,RS)} 1'

Output will be as follows.

projects.google.tests.inbox.document_01
projects.google.tests.inbox.document_02
projects.google.tests.inbox.global_02

Explanation: Using awk's gsub utility which is used for globally substitution and it's method is gsub(/regex_to_be_subsituted/,variable/new_value,current_line/variable), so here I am giving \\r\\n(point to be noted here I am escaping here \\ which means it will take it as a literal character) with RS(record separator, whose default value is new line) in the current line. Then 1 means, awk works on method of condition and action, so by mentioning 1 I am making condition as TRUE and no action is given, so default action print of current will happen.

EDIT: With a variable you could use as following.

var="projects.google.tests.inbox.document_01\r\nprojects.google.tests.inbox.document_02\r\nprojects.google.tests.inbox.global_02"
echo "$var" | awk '{gsub(/\\r\\n/,RS)} 1'
projects.google.tests.inbox.document_01
projects.google.tests.inbox.document_02
projects.google.tests.inbox.global_02

回答2:

inputData=$'projects.google.tests.inbox.document_01\r\nprojects.google.tests.inbox.document_02\r\nprojects.google.tests.inbox.global_02'
while IFS= read -r line; do
  line=${line%$'\r'}
  echo "$line"
done <<<"$inputData"

Note:

• The string is defined as string=$'foo\r\n', not string="foo\r\n". The latter does not put an actual CRLF sequence in your variable. See ANSI C-like strings on the bash-hackers' wiki for a description of this syntax.
• ${line%$'\r'} is a parameter expansion which strips a literal carriage return off the end of the contents of the variable line, should one exist.
• The practice for reading an input stream line-by-line (used here) is described in detail in BashFAQ #1. Unlike iterating with for, it does not attempt to expand your data as globs.

来源：https://stackoverflow.com/questions/46556202/split-string-using-r-n-using-ifs-in-bash