小企鵝開談 : [轉貼]Find Out If File Exists With Conditional Expressions

[ parameter FILE ]

test parameter FILE

[[ parameter FILE ]]

-e: Returns true value if file exists.
-f: Return true value if file exists and regular file.
-r: Return true value if file exists and is readable.
-w: Return true value if file exists and is writable.
-x: Return true value if file exists and is executable.
-d: Return true value if exists and is a directory.

$ [ -f /etc/passwd ] && echo "File exist" || echo "File does not exist"
$ [ -f /tmp/fileonetwo ] && echo "File exist" || echo "File does not exist"

$ [[ -f /etc/passwd ]] && echo "File exist" || echo "File does not exist"
$ [[ -f /tmp/fileonetwo ]] && echo "File exist" || echo "File does not exist"

$ [ -d /var/logs ] && echo "Directory exist" || echo "Directory does not exist"
$ [ -d /dumper/fack ] && echo "Directory exist" || echo "Directory does not exist"

$ [[ -d /var/logs ]] && echo "Directory exist" || echo "Directory does not exist"
$ [[ -d /dumper/fake ]] && echo "Directory exist" || echo "Directory does not exist"

[[ /etc/resolv.conf -ef /etc/resolv.conf ]] && echo "Same files" || echo "Noop"
[[ /etc/resolv.conf -ef /etc/passwd ]] && echo "Same files" || echo "Noop"

#!/bin/bash
FILE="$1"

if [ -f "$FILE" ];
then
   echo "File $FILE exist."
else
   echo "File $FILE does not exist" >&2
fi
Save and execute the script:
$ chmod +x script.sh
$ ./script.sh /path/to/file
$ ./script.sh /etc/resolv.conf

test -e filename
[ -e filename ]

test -f filename
[ -f filename ]

[ -f /etc/hosts ] && echo "Found" || echo "Not found"

Found

#!/bin/bash
file="/etc/hosts"
if [ -f "$file" ]
then
	echo "$file found."
else
	echo "$file not found."
fi

       -b FILE
              FILE exists and is block special
       -c FILE
              FILE exists and is character special
       -d FILE
              FILE exists and is a directory
       -e FILE
              FILE exists
       -f FILE
              FILE exists and is a regular file
       -g FILE
              FILE exists and is set-group-ID
       -G FILE
              FILE exists and is owned by the effective group ID
       -h FILE
              FILE exists and is a symbolic link (same as -L)
       -k FILE
              FILE exists and has its sticky bit set
       -L FILE
              FILE exists and is a symbolic link (same as -h)
       -O FILE
              FILE exists and is owned by the effective user ID
       -p FILE
              FILE exists and is a named pipe
       -r FILE
              FILE exists and read permission is granted
       -s FILE
              FILE exists and has a size greater than zero
       -S FILE
              FILE exists and is a socket
       -t FD  file descriptor FD is opened on a terminal
       -u FILE
              FILE exists and its set-user-ID bit is set
       -w FILE
              FILE exists and write permission is granted
       -x FILE
              FILE exists and execute (or search) permission is granted

if [ operator FileName ]
then
     echo "FileName - Found, take some action here"
else
   echo "FileName - Not found, take some action here"
fi

find /dir/name -type -f -exec command {} \;

find /path/to/dir -maxdepth 0 -empty -exec echo {} is empty. \;

find /path/to/dir -type d -empty -exec command1 arg1 {} \;

$ find "/tmp" -type f -exec echo Found file {} \;

Found file /tmp/_.c
Found file /tmp/orbit-vivek/bonobo-activation-server-ior
Found file /tmp/orbit-vivek/bonobo-activation-register.lock
Found file /tmp/_.vsl
Found file /tmp/.X0-lock
Found file /tmp/.wine-1000/server-802-35437d/lock
Found file /tmp/.wine-1000/cxoffice-wine.lock
Found file /tmp/ksocket-vivek/Arts_PlayObjectFactory
Found file /tmp/ksocket-vivek/Arts_SimpleSoundServer
Found file /tmp/ksocket-vivek/secret-cookie
Found file /tmp/ksocket-vivek/Arts_AudioManager
Found file /tmp/ksocket-vivek/Arts_SoundServer
Found file /tmp/ksocket-vivek/Arts_SoundServerV2
Found file /tmp/vcl.XXf8tgOA
Found file /tmp/Tracker-vivek.6126/cache.db
Found file /tmp/gconfd-vivek/lock/ior

$ [ "$(ls -A /path/to/directory)" ] && echo "Not Empty" || echo "Empty"

$ [ "$(ls -A /tmp)" ] && echo "Not Empty" || echo "Empty"

#!/bin/bash
FILE=""
DIR="/tmp"
# init
# look for empty dir
if [ "$(ls -A $DIR)" ]; then
     echo "Take action $DIR is not Empty"
else
    echo "$DIR is Empty"
fi
# rest of the logic

# Bourne/bash for loop example
for z in ~/projects/*.c; do
        test -f "$z" || continue
        echo "Working on $z C program..."
done

nullglob If set, bash allows patterns which match no files to expand to a null string, rather than themselves.
dotglob – If set, bash includes filenames beginning with a . in the results of pathname expansion.

#!/bin/bash
# Set the variable for bash behavior
shopt -s nullglob
shopt -s dotglob

# Die if dir name provided on command line
[[ $# -eq 0 ]] && { echo "Usage: $0 dir-name"; exit 1; }

# Check for empty files using arrays
chk_files=(${1}/*)
(( ${#chk_files[*]} )) && echo "Files found in $1 directory." || echo "Directory $1 is empty."

# Unset the variable  for bash behavior
shopt -u nullglob
shopt -u dotglob

$ ./script.sh /tmp
Files found in /tmp directory.
$ mkdir /tmp/foo
$ ./script.sh /tmp/foo
Directory /tmp/foo/ is empty.

## In ksh93, prefix ~(N) in front of the pattern
## For example, find out if *.mp4 file exits or not in a dir
cd $HOME/Downloads/music/
for f in ~(N)*.mp4; do
        # do something if file found
        echo "Working on $f..."
done

if [ ./* == "./*" ]; then
    echo "No new file"
    exit 1
fi

line 1: [: too many arguments

if [ "$(ls -A /path/to/dir)" ]; then
   echo "Not Empty"
else
   echo "Empty"
fi

if [ $(find $DIR_TO_CHECK -maxdepth 0 -type d -empty 2>/dev/null) ]; then
    echo "Empty directory"
else
    echo "Not empty or NOT a directory"
fi

if find /some/dir -mindepth 1 | read; then
   echo "dir not empty"
else
   echo "dir empty"
fi

[ `ls -1A . | wc -l` -eq 0 ] && echo "Current dir is empty." || echo "Current dir has files (or hidden files) in it."

[ `ls -1A . | wc -l` -eq 0 ] && \
echo "Current dir is empty." || \
echo "Current dir has files (or hidden files) in it."