Find files using shell script

Question

I have the below script which looks for the file in the current directory and evaluates to true if the file exists in the directory and evaluates to false if it does not

#!/bin/bash
printf "\n Please enter a file name "

read num3

if [ -f $num3 ]
then
printf "It is valid script "
else
printf "Invalid file name "
fi

How can i check for the presence of the files in some other directory rather than the present directory in which the script is written ?

Solution 1

Try this

#!/bin/bash
printf "\n Please enter a file name "
read num3
printf "\n Please enter the path to check "
read path2check

if find $path2check -name $num3 -print -quit |
   grep -q '^'; then
  echo "the file exists!"
else
  echo "the file does not exist!"
fi

Solution 2

[ -f $num3 ]

Doesn't make sense as you're applying the split+glob operator to the content of $num3.

[ -f "$num3" ]

Would check whether the $num3 path (absolute if it starts with a /, relative to the current working directory if not) resolves to a file that is of type regular or a symlink to a regular file.

If you want to check whether $num3 relative to a given directory is a regular file, just use:

dir=/some/dir
[ -f "$dir/$sum3" ]

You may want to check beforehand that $sum3 doesn't start with a / or doesn't contain a /.

Note that if $dir is /, that approach will not work on systems that treat //foo/bar paths specially. So you may want to treat the dir=/ case specially.

case $dir in
  /) file=$dir$num3
  *) file=$dir/$num3
esac
[ -f "$file" ]

To check that $num3 is a relative path (to a regular file) of any directory in the directory tree rooted at the current directory, best would be to use zsh instead:

files=(**/$num3(DN-.))
if (($#files > 0)); then
  echo "Success: $#files such file(s) found"
else
  echo Failure
fi

Solution 3

Consider this example where, i want to add a file if it is present at some location to my composite_firmware.bin image.

step1: export VSPA_IMAGE1=/path/where/image/is/located/file.bin from shell. step2: Add if file is found via script and append at location 0x200000 of composite_firmware.bin

if [ -f "$VSPA_IMAGE1" ]; then
 printf "\nAdding $VSPA_IMAGE1 to composite image\n"
 dd if=$VSPA_IMAGE1 of=composite_firmware.bin seek=2048 bs=1024
else
 printf "\nWarning!!!! export VSPA_IMAGE1 location/path"
fi

Comments

[Rohit Saluja]

I understood it till -print can you please explain the logic from the -quit ?

[roaima]

@Rohit man find

[Danura Selaka Senan]

-quit means that the find command will stop as soon as it finds the first instance

[Stéphane Chazelas]

Note that -name "$num3" (-name $num3 doesn't make sense) is not to find files whose name is $num3, but files whose name matches the $num3 pattern.

[Marek Zakrzewski]

printf there can be replaced with read -p 'Please enter a file name' num3 instead. Also you'd first run the check then command substitute the find as in < <( find ... )