Remove prefix and extension in Shell from file

Question

I want to extract filename by removing prefix and extension. e.g. file=foo_filename.txt

I am using this,but its not working.

${file#foo_%.txt}

Thanks

Be sure to check out [Parameter Expansion](http://mywiki.wooledge.org/BashGuide/Parameters#Parameter_Expansion) on Greg's Wiki. — w0ng, Jan 15 '14 at 21:39

score 2 · Answer 1 · answered Jan 15 '14 at 21:28

2

file="foo_filename.txt"
file=${file#foo_}
file=${file%.*}
echo "$file"

answered Jan 15 '14 at 21:28

that other guy

score 1 · Answer 2 · edited May 23 '17 at 12:21

1

You got it almost right:

file=foo_filename.txt ;  echo ${file%.txt}

Or for example in one step with sed:

file=foo_filename.txt ;  echo ${file} | sed 's/^foo_\(.*\)\..*/\1/'

Yet another method:

file=foo_filename.txt ; basename -s .txt ${file#foo_}

edited May 23 '17 at 12:21

Community

answered Jan 15 '14 at 21:28

Jakub Kotowski

I want to remove foo_ as well,which is the prefix. – Rgeek Jan 15 '14 at 21:29
then you have to do it in two steps as in the other answer – Jakub Kotowski Jan 15 '14 at 21:29
It might be worth noting that the "one step" methods are about a thousand times slower than the two step method due to the required forks. They may also fail outright if the filename contains various kinds of whitespace and special characters. – that other guy Jan 15 '14 at 22:40
that's true that they are slower – Jakub Kotowski Jan 15 '14 at 22:57

2 Answers2