find a file in a folder using a bash script (linux) - linux

Question

need to create a text file within the folder (done)
I use nano to create a file called spn.txt and input some data inside. (done)
4:3
5:5
1:5
3:1
4:3
4:1
create a script
2.1. ask user to input the name of the text file (txt) in the folder
2.2 find the txt file
if there no file found
ask user to input the name of the text file (txt) in the folder
2.3. if have the file read the value of the file and display the number of the left hand side
#!/bin/bash
echo "please input file name with extension (e.g spn.txt)"
read filename
how to create a while command that
look for the filename
if filename not found in the folder, ask user to input file name
if file name is found. display the number of the left hand side.

Answer 1

Disclaimer: this does not define a loop and hence maybe does not answer your question.
This said, if you need to quickly manage some user interactions you can try Zenity
#!/bin/bash
FILE=`zenity --file-selection --title="Select a File"`
case $? in
0)
echo "\"$FILE\" selected.";;
1)
echo "No file selected.";;
-1)
echo "An unexpected error has occurred.";;
esac
Obviously, you need Zenity to be installed, which can be a problem regarding the portability. The advantage is that you can create "complex" input forms. It all depends on your context.

Answer 2

You can easily achieve this with the following commands:
#!/bin/bash
filename=""
echo -e "\nStarting script ... You can press Ctrl+C anytime to stop program execution.\n"
##### Ensure the user will provide a valid file name #################
while [[ ! -r "${filename}" ]] ; do
echo -n "Please, enter the file name: (e.g spn.txt): "
read filename
done
#
# At this point we have a valid filename supplied by the user
# So, prints the left values of it, using the ':' as a field delimiter
cut -d':' -f 1 ${filename}
The cut command is used above with the following parameters:
-d':' -> Set the delimiter to ':'
-f 1 -> Display just the field number 1. If you would like to display just the right numbers, you could use -f 2 here, because assuming the field delimiter is the character ':', the right numbers are located on the second field.

Answer 3

#!/bin/bash
### Maintainer: Vrej Abramian, Git: https://github.com/vrej-ab, vrejab#gmail.com ###
### Configuration Parameters Start ###
request_filename_message="Please input file name with extension (e.g spn.txt): "
filename_variable='filename'
attempts_count='3'
_file_check='' # Leave this empty
### Configuration Parameters End ###
### Finctions Start ###
# Unified messages
echo_green(){ echo -en "\033[0;32m$*" ;echo -e "\033[0;0m"; }
echo_yellow(){ echo -en "\033[1;33m$*" ;echo -e "\033[0;0m"; }
echo_red(){ echo -en "\033[0;31m$*" ;echo -e "\033[0;0m"; }
# Promt and request to input a valid `filename`
request_filename_function(){
# Use `read` with `-p` option which will prompt your message and
# avoid using extra `echo` command.
read -p "${request_filename_message}" "${filename_variable}"
}
# Check if the inputed filename is accessible
file_check(){
if [ -r "${!filename_variable}" ] ;then
echo_green "\n[INFO]: ${!filename_variable} - file is available."
_file_check='pass'
else
echo_red "\n[ERROR]: ${!filename_variable} - file is either un-available or un-accessible."
_file_check='fail'
fi
}
# If provided `filename` wouldn't be available, this provides retrying chances
retry_function(){
local i=1
while [ "${_file_check}" != 'pass' ] && [ ${i} -lt ${attempts_count} ] ;do
echo_yellow "\n[WARN]: Please tray again - $(( attempts_count-i )) times left!"
local i=$(( ++i ))
request_filename_function
file_check
done
if [ ${i} -gt ${attempts_count} ] ;then
echo_red "[FATAL]: No more attempts, Bye-Bye...\n"
exit 1
fi
}
# Get the provided file's first column data - assuming that the delimiter is a ':' character in the file
left_handside_numbers_function(){
cat "${1}" | awk -F':' '{print $1}'
}
# Filter the user defined param,eters in this script
defined_parameters_function(){
defined_parameters=$(sed -n '/^### Configuration Parameters Start ###/,/^### Configuration Parameters End ###/p' "${0}" | \
grep -v '^\#' | awk -F'=' '{print $1}')
defined_parameters="${filename_variable} ${defined_parameters}"
}
# Run cleanup jobs
cleanup_function(){
unset ${defined_parameters}
}
### Functions End ###
### Script Body Start ###
request_filename_function
file_check
retry_function
left_handside_numbers_function "${!filename_variable}"
defined_parameters_function
cleanup_function
### Script Body End ###
exit 0