testing for file existence bash

Question

I've read some other questions, and I feel like i'm doing exactly as everybody else is, but I just can't find the files.

file="~/.todo/$1.task"
if [ ! -f "$file" ]; then
    echo "Error. Task ~/.todo/$1.task not found."
    ls ~/.todo/
    exit 1
fi

This is inside of a function when del gets called....so with this command, here's the output:

$ ./todo.sh del 19
Error. ~/.todo/19.task not found.
10.task  13.task  16.task  1.task  6.task  9.task     tododatesorted
11.task  14.task  18.task  3.task  7.task  taskno
12.task  15.task  19.task  4.task  8.task  tododates

How come it says it doesn't exist when really it does? I've tried -e and -f flags although I don't fully understand the difference.

Kevin · Accepted Answer · 2013-03-09 21:46:20Z

7

The The difference is in pathname expansion. When you have ~ unquoted, the shell expands it to your home directory. But when it's within quotation marks, as you have it, it does not get expanded. E.g.

$ file="~"; echo $file
~
$ file=~; echo $file
/Users/kevin

You can fix your script in one of two ways:

Drop the quotation marks: file=~/.todo/$1.task. In the case of variable assignment like this, whitespace in $1 won't break the command, but you can quote just the $1 if you want.
Use $HOME instead: file="$HOME/.todo/$1.task"

answered Mar 9, 2013 at 21:46

Kevin

56.6k15 gold badges107 silver badges139 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Jim Lewis · Accepted Answer · 2013-03-09 21:43:52Z

1

I don't think tilde expansion is happening when you check "$file". So the filename it's looking for still has the tilde character in it, rather than expanding to the home directory.

answered Mar 9, 2013 at 21:43

Jim Lewis

45.4k7 gold badges86 silver badges97 bronze badges

1 Comment

Étienne Miret Over a year ago

Indeed. But the tilde expansion does happen if you remove the quotes arround $file.

Joe Alamo · Accepted Answer · 2019-07-16 12:19:52Z

0

In Bash you can do this:

unexpanded_file="~/example.txt"
file="${unexpanded_file/#\~/$HOME}"

This should replace ~ with $HOME

answered Jul 16, 2019 at 12:19

Joe Alamo

1332 silver badges7 bronze badges

Comments

Salvatore · Accepted Answer · 2013-03-09 21:44:45Z

-4

Try to get rid of the ';' after the ]...I'm not sure, I can't try it.

answered Mar 9, 2013 at 21:44

Salvatore

1,1954 gold badges22 silver badges45 bronze badges

1 Comment

SetSlapShot Over a year ago

that's just the syntax for putting multiple things on one line.

Collectives™ on Stack Overflow

testing for file existence bash

4 Answers 4

Comments

1 Comment

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

1 Comment

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related