get full path of a file

[philipose]

Hi unix gurus,
Is there a way to get the complete path of a file.

ie say my pwd is /root/mydir

>> pwd
>> /root/mydir
>> ls ../myfile.xls

is there any function that you take ../myfile.xls as input and return /root ?
Any suggestions in the right direction are welcome

Thanks
Philipose

 

[kHz]

if pwd is in your path, which should return the path.

 

[columb]

Er... It's not quite as simple as that. The example given is ../myfile.xls and .. is the parent directory, not the current directory. The parent directory should be replaced by $(dirname $(pwd))

Try

#!/bin/ksh

[[ $# -ne 1 ]] && { echo No file name; exit; }

echo $1 | sed 's!\.\.!'$(dirname $(pwd))'!' | sed 's!\.!'$(pwd)'!'

The first sed expression, using ! as separator, replaces .. with the parent directory, the second replaces . with the current directory. sed gurus could probably make this simpler and quicker

Ceci n'est pas une signature
Columb Healy

 

[philipose]

columb,
thanks for the suggestion. i need a little more info from this particular absolute path finder.

>> pwd
>> /root/mydir
>> ls ../myfile.xls
f(../myfile.xls) should return /root
f(./myfile.xls) should return /root/mydir
f(~/myfile.xls) should return /myhome
f(/root/mydir/myfile.xls) should return /root/mydir
f(./../../myfile.xls) should return /

thanks
philipose

 

[columb]

That's a lot more complex

Effectively the routine should identify and replace . .. and ~ anywhere in the file path and replace it with the absolute path.

So, in pseudo code

start at current workign directory
for each part of supplied path
  amend directory
return path

And in ksh

#!/bin/ksh -xv

# Check for passed path
[[ $# -eq 1 ]] || { echo no param; exit 1; }
#If passed path starts with / it's absolute, otherwise relative
expr $1 : "/.*" > /dev/null && ret_path="" || ret_path=$(pwd)

#split path into sections separated by /
for bit in $(dirname $1 | tr '/' ' ')
do
  # if .. move up a level
  [[ $bit = '..' ]] && { ret_path=$(dirname $ret_path); continue; }
  # if . nfa
  [[ $bit = '.' ]] && continue
  # else add to path
  ret_path=${ret_path}/${bit}
done
 
echo $ret_path

This code has a bug in it. It doesn't deal gracefully with, from your example, ../../root/mydir which is a valid path.

Ceci n'est pas une signature
Columb Healy

 

[philipose]

Thanks Columb for your suggestion. I will try it out. Another thought came to me. I think the combining the basename command and the sed command might give the answer I am looking for. I think the basename command will take care of all ., ~, and .. and return absolute paths. I have to try it out yet.
thanks again
philipose

 

[philipose]

I got things working the below way. Thanks very much for your help. The variable abspath should contain the absolute path after running the code

# Get filename with extension of file
filename=`/usr/bin/basename $file`

# Get present working directory
cpath="$PWD"
# Get path (this could be relative path) of file
path=`/usr/bin/echo $file | /usr/bin/sed -e 's/filename$//'`

# Get absolute path of the file to be archived
usr/bin/cd "$path"
abspath=$PWD
usr/bin/cd $cpath

 

[philipose]

minor modification

# Get filename with extension of file
filename=`/usr/bin/basename $file`

# Get present working directory
cpath="$PWD"
# Get path (this could be relative path) of file
path=`/usr/bin/echo $file | /usr/bin/sed -e 's/filename$//'`

# Get absolute path of the file to be archived
cd "$path"
abspath=$PWD
cd $cpath