How to get only filename using sed

basename from the GNU coreutils can help you doing this job:

$ basename /root/video.mp4
video.mp4

If you already know the extension of the file, you can invoke basename using the syntax basename NAME [SUFFIX] in order to remove it:

$ basename /root/video.mp4 .mp4
video

Or another option would be cutting everything after the last dot using sed:

$ basename /root/video.old.mp4 | sed 's/\.[^.]*$//'
video.old

The easiest solution is remove everything until last appearance of /:

echo /root/video.mp4 | sed 's/.*\///'

Use any of the followings ways:

out_file="${in_file##*/}"

out_file="$(basename $in_file)"

out_file="$(echo $in_file | sed 's=.*/==')"

out_file="$(echo $in_file | awk -F"/" '{ print $NF }')"

ps. You get the same string because in your statement \(.*\.\) matches to the string from the beginning until dot (/root/video.) and then you manually add .mp4 which is the same as in you original string. You should use s=.*\([^/]*\)=\1= instead.

Update: (First one is fixed now)

To get the only filename without extension you can :

out_file="$(echo $in_file | sed 's=.*/==;s/\.[^.]*$/.new_ext/')"

out_file="$(echo $in_file | sed 's=\([^/]*\)\.[^./]*$=\1.new_ext=')"

out_file="$(echo $in_file | awk -F"/" '{ gsub (/\.[^/.]*$/,".new_ext",$NF);print $NF }'