sh - split string by delimiter

Question

code

s='id;some text here with possible ; inside'
IFS=';' read -r id string <<< "$s"
echo "$id"

error

restore.sh: 2: restore.sh: Syntax error: redirection unexpected

bash version GNU bash, version 4.2.37(1)-release (x86_64-pc-linux-gnu)

Solution 1

You seem to be using sh to execute the script. Herestrings aren't supported in sh; hence the error.

Ensure that you're using bash to execute the script.

Solution 2

A here string is just a shortcut for a small here document. This should work in any POSIX shell:

s='id;some text here with possible ; inside'
IFS=';' read -r id string <<EOF
$s
EOF
echo "$id"

Solution 3

save it in file split

#!/bin/sh

string=$1
c=0

while [ $c -le $3 ] 
do

val1=`echo "$string" |sed 's/\(^[^'$2']*\)\('$2'\+\)\(.*$\)/\1/'`
string=`echo "$string" |sed 's/\(^[^'$2']*\)\('$2'\+\)\(.*$\)/\3/'`

if [ "$val1" == "$string" ]
then
string=''
fi

if [ "$val1" == "" ]
then
let c=$3
fi

let c=c+1

done

echo $val1 

and it work:

root@IPHONE:~# ./split 'a;b;c' ';' 0
a
root@IPHONE:~# ./split 'a/b/c' '\/' 0
a
root@IPHONE:~# ./split 'a/b/c' '\/' 2
c
root@IPHONE:~# ./split 'a/b/c' '\/' 1
b

Comments

[clarkk]

what is the difference between sh and bash?

[Radu Rădeanu]

@clarkk Difference between sh and bash

[chepner]

Some Linux distributions use dash (not bash) as the shell that implements sh. dash is (mostly?) limited to the features specified by the POSIX specification, without the extra features like <<< implemented by bash.

[clarkk]

how can I then do this operation with sh?

[devnull]

@clarkk Right; as mentioned in the answer herestrings aren't supported in sh.

[devnull]

@clarkk Maybe you could use cut. echo "$s" | cut -d; -f1 would return the first field.

[clarkk]

this works echo "$s" | cut -d";" -f1 but how can I assign it into a variable?

[anishsane]

@clarkk: Use var=$(echo "$s" | cut -d";" -f1)

[Jess]

Am new to shell but from Java background. Can you explain your code ?

[yassen]

@Jess: very late comment but anyway, my two cents: POSIX read expects a line on standard input, reads that and splits it using $IFS contents as a separator, then assigns each chunk to variables given as arguments to read (id and string; id getting the first chunk and string getting all the remaining chunks). The trick with the two EOFs is called a "heredoc" and AFAIK is the only way to send that string to read's standard input. See also pubs.opengroup.org/onlinepubs/9699919799/utilities/read.html‌​.