Is there a command to display message “Yes” if a particular file exists? No need to give functionality if the file does not exist.
You can use this simple script:
#!/bin/bash if [[ -f $1 ]]; then echo "Yes" exit 0 else exit 1 fi
Save it as
file-exists.sh. Then, in the Terminal, type
chmod +x file-exists.sh.
Use it like:
./file-exists.sh FILE where you replace
FILE with the file you want to check, for example:
Yes will be printed to the Terminal, and the program will exit with status 0 (success). If the file does not exist, nothing will be printed and the program will exit with status 1 (failure).
If you're curious why I included the
exit command, read on...
What's up with the
exit causes normal process termination. What this means is, basically: it stops the script. It accepts an optional (numerical) parameter that will be the exit status of the script that called it.
This exit status enables your other scripts to use your
file-exists script and is their way of knowing the file exists or not.
A simple example that puts this to use is this script (save it as
#!/bin/bash echo "Enter a filename and I will tell you if it exists or not: " read FILE # Run `file-exists.sh` but discard any output because we don't need it in this example ./file-exists.sh $FILE &>> /dev/null # #? is a special variable that holds the exit status of the previous command if [[ $? == 0 ]]; then echo "$FILE exists" else echo "$FILE does not exist" fi
Do the usual
chmod +x file-exists-cli.sh and then run it:
./file-exists-cli.sh. You'll see something like this:
File exists (
➜ ~ ./file-exists-cli.sh Enter a filename and I will tell you if it exists or not: booleans.py booleans.py exists
File does not exist (
➜ ~ ./file-exists-cli.sh Enter a filename and I will tell you if it exists or not: asdf asdf does not exist
In the bash shell on the command line.
if [[ -f /path/to/file ]]; then echo "Yes"; fi
This uses the bash conditional operator
-f, and is checking whether the file exists and is a regular file. If you want to test for any files including directories and links then use
The shortest command for doing what you want is:
test -e FILENAME && echo Yes
test -e will test whether the name given exists in the file system. (You can use
test -f to restrict to regular files only. See
man test for more.)
If the condition given evaluates to true, then
test returns a successful exit status (otherwise it returns a failure status). We combine the two commands using
&&, which means "execute the next command if the previous command exited with a success status". The next command simply prints
Yes on standard output; in the case of an interactive shell, on the terminal.
This avoids the additional textual material of an
if statement, yet gives the same result. Using
&& (or its opposite,
||) to tie commands together works well when only a single command is involved. If you want to do more than execute a single command in response to a single command's exit status, then using the
if syntax quickly becomes much more readable.
As already pointed out in other answers, the equivalent
if style construct would be:
if test -e FILENAME; then echo Yes; fi
if test -e FILENAME then echo Yes fi
For these purposes,
test are equivalent, except that
[ demands a terminating
To skin this type of question there's multiple ways, and here's another one : use
find command with
-exec flag . The path to file can be split into two parts
find /etc which sets directory and
-name FILENAME which specifies filename (duh!) .
-maxdepth will keep
find working with
/etc directory only and won't descend into subdirectories
adminx@L455D:~$ find /etc -maxdepth 1 -name passwd -exec printf "YES\n" \; YES adminx@L455D:~$ find /etc -maxdepth 1 -name passwd1 -exec printf "YES\n" \; adminx@L455D:~$
Another way , via
adminx@L455D:~$ stat /etc/passwd1 &>/dev/null && echo YES adminx@L455D:~$ stat /etc/passwd &>/dev/null && echo YES YES
And alternatively via python :
>>> import os >>> if os.stat('/etc/passwd'): ... print 'YES' ... YES >>> if os.stat('/etc/passwd1'): ... print 'YES' ... Traceback (most recent call last): File "<stdin>", line 1, in <module> OSError: [Errno 2] No such file or directory: '/etc/passwd1'
Or a short command line alternative :
python -c "from os.path import exists; print 'Yes' if exists('/etc/fstab') else '' "