Shell Programming and Scripting

Hi I am a complete novice with sed and want to use sed to replace this line in the input file

/data/folder/date/etc/etc/etc/etc/etc/name

with

/data/folder/date/etc/etc/etc/etc/etc/$name

where I input the variable $name

trouble is is there anyway I don't have to write out the whole line to be replaced (due to the length and that the name various every time so I don't want to have to edit the script everytime, which is the point of writing a script!). So how do I specify the SED command so that it recognises the line beginning with /data/folder/etc and replace only the last variable?

Many thanks
Robert

Hi, try:

Code:

sed '/\/data\/folder\//s/[^/]*$/$&/' file

Thanks scrutiniser. Would you mind explaining what the code means? I am trying to learn thanks so much!

Sure:

Code:

/\/data\/folder\// # If a line contains "/data/folder/",
s/[^/]*$/$&/       # then substitute zero to more (*) characters that are not a "/" ([^/]) at
                   # the end of the line ($), by the same string (&), prepended by a dollar sign ($)

Hi Scrutinizer

Not sure if you have misunderstood me or I still getting myself confused.

I am trying to replace a line in a file where it contains name of the last folder (folder name 1) with a long pathname (see eg in first thread), and I want to write a script containing a SED command where I specify the name of the new folder which is to replace (folder name 1).

The point of the sed command is folder name 1 is different everytime I use the script, it only needs to recognise that line and replace folder name 1 with the new folder name which I input when I call in the script.

Thanks, I am quite clueless with SED at the moment.

You need to be a bit more specific I'm afraid... could you show a representative sample of input, desired output, attempts at a solution and specify what OS and version you are using?

I am using zsh as the shell

in my file test.txt there is a line which read

/data/folder1/folder2/folder3/folder4/folder5/folder name1

and I want to write a script file containing SED command which reads in test.txt and replace folder name1 with a new folder name that I specify when I call in the SED, something like

new_folder_name=ABCD
sed s:/data/folder1/folder2/folder3/folder4/folder5/folder name1:/data/folder1/folder2/folder3/folder4/folder5/$new_folder_name

as a result the script will replace that line in test.txt with the new folder name ABCD.

Trouble is folder name 1 would be different everytime I call the scripts, so to avoid having to edit the SED command everytime is there a generic way I can write the SED command so that it only need to recognises that line in the file and replace the last folder name with the new folder name I specify when I execute the script? New folder name would be used as a variable here.

Thanks