UNIX for Dummies Questions & Answers

following situation...

- bourne shell script
- sb. should entry a path and the script should look if the path exists, when not it should restart the Input

...
echo "path\c"
read Inp
if [$Inp = ?????] ; then
echo " path doesn't exist, try again... "
(how to go back to the Inp?????)
else
echo " path exists "
.....
fi
...

thx for any advice...

is there a chance by 'pathchk'? for example...

echo "path\c"
read Inp>file
VALID=pathchk `cat file`
if [$VALID != 0] ; then
echo " path doesn't exist, try again... "
(how to go back to the Inp?????)
else
echo " path exists "
..........
fi
..

is there also sth. like for files? like checking if the file is present and then return a zero.....

for example for files...

echo "path\c"
read Inp1>file1
VALID1=pathchk `cat file1`
if [$VALID1 != 0] ; then
echo " path doesn't exist, try again... "
(how to go back to the Inp1?????)
else
echo " path exists "
cd `cat file1` (will not work, because of the directory..how to solve?)
cd `cat users/abc/file1`(should work)
echo "searching which file? \c"
read Inp2
find . -name "`cat file2`" >file3
VALID2=`cat file3`
if [ -f $VALID2 ] ; then
echo "$VALID2 exists"
....
else
echo "not existing"
(how to go back to the Inp2?????)
fi
..
fi
..

no help needed anymore...thx

The test command evaluates the expression expr and, if its value is True, returns a zero (true) exit status; otherwise, a nonzero (false) exit status is returned. test also returns a nonzero exit status if there are no arguments. The following primitives are used to construct expr: -r file True if file exists and is readable.
-w file True if file exists and is writable.
-x file True if file exists and is executable.
-f file True if file exists and is a regular file.
-d file True if file exists and is a directory.
-c file True if file exists and is a character special file.
-b file True if file exists and is a block special file.
-p file True if file exists and is a named pipe (fifo).
-u file True if file exists and its set-user-ID bit is set.
-g file True if file exists and its set-group-ID bit is set.
-k file True if file exists and its sticky bit is set.
-s file True if file exists and has a size greater than zero.
-h file True if file exists and is a symbolic link.
-t [fildes] True if the open file whose file descriptor number is fildes (1 by default) is associated with a terminal device.
-z s1 True if the length of string s1 is zero.
-n s1 True if the length of the string s1 is non-zero.
s1 = s2 True if strings s1 and s2 are identical.
s1 != s2 True if strings s1 and s2 are not identical.
s1 True if s1 is not the null string.
n1 -eq n2 True if the integers n1 and n2 are algebraically equal. Any of the comparisons -ne, -gt, -ge, -lt, and -le can be used in place of -eq.

These primaries can be combined with the following operators: ! Unary negation operator.
-a Binary AND operator.
-o Binary OR operator (-a has higher precedence than -o).
( expr ) Parentheses for grouping.


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by the way, go back to the Input by while->break....

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also have a look here...

http://www.washington.edu/computing/...g/125/ctl.html