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Extract first line of a file and use as filename

 
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# 1  
Old 06-30-2010
Extract first line of a file and use as filename
I am trying to find a way to create a script which will extract the first line of a file and then rename the file (or create a new file with the same content as the old file) using the first line as the name. The first line being a single word, that is. I am hopeless at programming, if anyone can help you I would appreciate it very much!!
# 2  
Old 06-30-2010
Hi, welcome to the forum. This would be one way of doing that:
Code:
mv "$file" "$(head -1 "$file")"

These 2 Users Gave Thanks to Scrutinizer For This Post:
chen.xiao.po phoenix_nebula
# 3  
Old 06-30-2010
Thank you!! That works like a charm. It always looks so much easier when someone else does it Smilie

---------- Post updated at 07:55 PM ---------- Previous update was at 05:19 PM ----------

You wouldn't happen to know how to make it iterate over every file in a directory? I've tried this:

for i in *; do mv $i "$(head -1 $i)"; done

Which doesn't work, and which I don't know enough to why it doesn't work. Well, it does rename the files after which terminal no longer seems to recognize them as files. Just using * in place of filename causes it to use the first line from every file...
# 4  
Old 07-01-2010
Hi, don't forget the double quotes.. See if this works better.

Code:
for i in *; do mv "$i" "$(head -1 "$i")"; done

Are you sure each and every file contains a strictly a file name on the first line?

To get an idea of what your command does you can do this:
Code:
for i in *; do echo mv "$i" "$(head -1 "$i")"; done

Last edited by Scrutinizer; 07-01-2010 at 03:37 AM..
# 5  
Old 07-01-2010
Similar idea but with some error handling. Also deal with unlimited number of filenames, filenames containing spaces and what happens when the script is run a second time.
When tested, remove "echo" from the "mv" line.

Code:
#!/bin/ksh
ls -1d * | while read FILENAME1
do
        # Ignore if not a regular file
        if [ ! -f "${FILENAME1}" ]
        then
                continue
        fi
        # Bypass empty file
        if [ ! -s "${FILENAME1}" ]
        then
                echo "Empty file : ${FILENAME1}"
                continue
        fi
        # Extract filename from first record
        FILENAME2=`head -1 "${FILENAME1}"`
        if [ -f "${FILENAME2}" ]
        then
                echo "File from ${FILENAME1} aleady exists: ${FILENAME2}"
                continue
        fi
        # Rename file (remove echo when tested)
        echo mv "${FILENAME1}" "${FILENAME2}"
done

# 6  
Old 07-01-2010
Thanks!! I haven't tried the second solution, but I will. The first works, I figured out the python script creating the files was adding a space. Once I fixed that everything started working. Thank you!
 
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