Sed with Regexp not working?

I'm trying to search in all files a text and replace it with the word EXAMPLE. I do the following:

for f in /home/testu/zz*; do
sed -i "s/&VAR1s*=s*'?[1]{4}'?/EXAMPLE/g" "$f"
done


It gives no error, the files seems to be "updated" in the filesystem, but they wont get changed. If I test that regexp with grep command it works fine, so it must be something about the regexp with the sed command but dunno what.

Any help?

Are you aware that [1]{4} matches 1111? Is that your intention?
– Wiktor Stribiżew
Jun 29 at 8:14

[1]{4}

1111

Ah, use sed -i "s/&VAR1s*=s*'?1{4}'?/EXAMPLE/g" or sed -i "s/&VAR1[[:blank:]]*=[[:blank:]]*'?1{4}'?/EXAMPLE/g"
– Wiktor Stribiżew
Jun 29 at 8:24

sed -i "s/&VAR1s*=s*'?1{4}'?/EXAMPLE/g"

sed -i "s/&VAR1[[:blank:]]*=[[:blank:]]*'?1{4}'?/EXAMPLE/g"

Well, it works in GNU sed. Another variation: sed -i "s/&VAR1[[:blank:]]*=[[:blank:]]*'{0,}1{4}'{0,}/EXAMPLE/g", or sed -i -E "s/&VAR1[[:blank:]]*=[[:blank:]]*'?1{4}'?/EXAMPLE/g"
– Wiktor Stribiżew
Jun 29 at 8:27

sed -i "s/&VAR1[[:blank:]]*=[[:blank:]]*'{0,}1{4}'{0,}/EXAMPLE/g"

sed -i -E "s/&VAR1[[:blank:]]*=[[:blank:]]*'?1{4}'?/EXAMPLE/g"

Did you see my examples? If you use sed -i '...' you must use 1{4,} and if you use sed -i -E '...', you may use 1{4}. You do not need [...] around 1 char, remove them.
– Wiktor Stribiżew
Jun 29 at 8:33

sed -i '...'

1{4,}

sed -i -E '...'

1{4}

[...]

So, does anything work from the ideone.com/4XGQrR? What is your sed --version? Mine says sed (GNU sed) 4.2.2
– Wiktor Stribiżew
Jun 29 at 8:55

sed --version

sed (GNU sed) 4.2.2

2 Answers
2

Your current sed command parses the regular expression as a POSIX BRE compliant pattern.

sed

In BRE POSIX, ? matches a literal ? char, and { / } also match literal { / } chars. To make a range quantifier in a BRE POSIX pattern, you need to escape {...}, {min,max}.

?

?

{

}

{

}

{...}

{min,max}

The [1] is equal to 1, so the brackets are quite redundant here.

[1]

1

To fix your pattern, you may replace ? with {0,1} (0 or 1 occurrences) and {4} with {4}:

?

{0,1}

{4}

{4}

sed -i "s/&VAR1s*=s*'{0,1}1{4}'{0,1}/EXAMPLE/g" "$f"


Thanks to Wiktor Stribiżew tips, we got the solution (SSED GNU 4.1.5). The resulting regexp works with grep and sed. The code was a mix of solutions at the end.

sed -i "s/&VAR1s*=s*'{0,}1{4}'{0,};{0,}/EXAMPLE/g" "$f"


A few things:

Things like [[:blank:]] caused error of input file.

My sed version didnt support -E, so the {} had to be escaped, didn't know that :)

Thanks again Wiktor!

To thank me, please consider accepting/upvoting my answer
– Wiktor Stribiżew
Jun 29 at 10:28

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