I searched and couldn't find anything, maybe I can't understand the problem properly.
I have a bash function who read files in current dir and sub dir's, I'm trying to arrange the text and analyze the data but somehow I'm losing lines if I'm using pipeline.
the code:
function recursiveFindReq {
for file in *.request; do
if [[ -f "$file" ]]; then
echo handling "$file"
echo ---------------with pipe-----------------------
cat "$file" | while read -a line; do
if (( ${#line} > 1 )); then
echo ${line[*]}
fi
done
echo ----------------without pipe----------------------
cat "$file"
echo
echo num of lines: `cat "$file" | wc -l`
echo --------------------------------------
fi
done
for dir in ./*; do
if [[ -d "$dir" ]]; then
echo cd to $dir
cd "$dir"
recursiveFindReq "$1"
cd ..
fi
done
}
the output is:
losing lines even when they meet requirements
I marked with 2 red arrows the place I'm losing info
I have a text file containing the list of files like this:
A file1.gz file2.gz
B file3.gz file4.gz
C file5.gz file6.gz
D file7.gz file8.gz
...
A,B,C,D, ... are the name of the samples which are located in the first column and I want to make subdirectories with the name of the samples and move related files (located in second and third columns) of each samples to its own directories. How can I make a loop for doing this?
When the fields in your textfile are seperated with spaces (and your dirs and filenames have no spaces), you can use
while read -r dir file1 file2; do
mkdir -p "${dir}"
if [ ! -d "${dir}" ]; then
echo "Something strange with ${dir}, I do not know what to do."
exit 1
fi
if [ -f "${file1}" ]; then
mv "${file1}" "${dir}"
fi
if [ -f "${file2}" ]; then
mv "${file2}" "${dir}"
fi
done < textfile
This will work with a fixed nr of columns. When you want to support an unknown nr of files on each line, you must change this a bit:
while read -r dir files; do
mkdir -p "${dir}"
if [ ! -d "${dir}" ]; then
echo "Something strange with ${dir}, I do not know what to do."
exit 1
fi
for file in ${files}; do
if [ -f "${file}" ]; then
mv "${file}" "${dir}"
fi
done
done < textfile
I am writing a shell script to read all the files in the give directory by the user input then count how many files with that extension. I just started learning Bash and I am not sure why it this not locating the files or reading the directory. I am only putting 2 example but my count is always 0.
This is how I run my script
$./check_ext.sh /home/user/temp
my script check_ext.sh
#!/bin/bash
count1=0
count2=0
for file in "ls $1"
do
if [[ $file == *.sh ]]; then
echo "is a txt file"
(( count1++ ))
elif [[ $file == *.mp3 ]]; then
echo "is a mp3 file"
(( count2++ ))
fi
done;
echo $count $count2
"ls $1" doesn't execute ls on $1, it just a plain string. Command substitution syntax is $(ls "$1")
However there is no need to use ls, just use globbing:
count1=0
count2=0
for file in "$1"/*; do
if [[ $file == *.sh ]]; then
echo "is a txt file"
(( count1++ ))
elif [[ $file == *.mp3 ]]; then
echo "is a mp3 file"
(( count2++ ))
fi
done
echo "counts: $count1 $count2"
for file in "$1"/* will iterate through all the files/directories in the directory denoted by $1
EDIT: For doing it recursively inside a directory:
count1=0
count2=0
while IFS= read -r -d '' file; do
if [[ $file == *.sh ]]; then
echo "is a txt file"
(( count1++ ))
elif [[ $file == *.mp3 ]]; then
echo "is a mp3 file"
(( count2++ ))
fi
done < <(find "$1" -type f -print0)
echo "counts: $count1 $count2"
POSIXly:
count1=0
count2=0
for f in "$1"/*; do
case $f in
(*.sh) printf '%s is a txt file\n' "$f"; : "$((count1+=1))" ;;
(*.mp3) printf '%s is a mp3 file\n' "$f"; : "$((count2+=1))" ;;
esac
done
printf 'counts: %d %d\n' "$count1" "$count2"
You can use Bash arrays for this too: if you only want to deal with extensions sh and mp3:
#!/bin/bash
shopt -s nullglob
shs=( "$1"/*.sh )
mp3s=( "$1"/*.mp3 )
printf 'counts: %d %d\n' "${#shs[#]}" "${#mp3s[#]}"
If you want to deal with more extensions, you can generalize this process:
#!/bin/bash
shopt -s nullglob
exts=( .sh .mp3 .gz .txt )
counts=()
for ext in "${exts[#]}"; do
files=( "$1"/*."$ext" )
counts+=( "${#files[#]}" )
done
printf 'counts:'
printf ' %d' "${counts[#]}"
echo
If you want to deal with all extensions (using associative arrays, available in Bash ≥4)
#!/bin/bash
shopt -s nullglob
declare -A exts
for file in "$1"/*.*; do
ext=${file##*.}
((++'exts[$ext]'))
done
for ext in "${!exts[#]}"; do
printf '%s: %d\n' "$ext" "${exts[$ext]}"
done
Sorry for asking this question again. I have already received answer but with using find but unfortunately I need to write it without using any predefined commands.
I am trying to write a script that will loop recursively through the subdirectories in the current directory. It should check the file count in each directory. If file count is greater than 10 it should write all names of these file in file named "BigList" otherwise it should write in file "ShortList". This should look like:
---<directory name>
<filename>
<filename>
<filename>
<filename>
....
---<directory name>
<filename>
<filename>
<filename>
<filename>
....
My script only works if subdirectories don't include subdirectories in turn.
I am confused about this because it doesn't work as I expect.
Here is my script
#!/bin/bash
parent_dir=""
if [ -d "$1" ]; then
path=$1;
else
path=$(pwd)
fi
parent_dir=$path
loop_folder_recurse() {
local files_list=""
local cnt=0
for i in "$1"/*;do
if [ -d "$i" ];then
echo "dir: $i"
parent_dir=$i
echo before recursion
loop_folder_recurse "$i"
echo after recursion
if [ $cnt -ge 10 ]; then
echo -e "---"$parent_dir >> BigList
echo -e $file_list >> BigList
else
echo -e "---"$parent_dir >> ShortList
echo -e $file_list >> ShortList
fi
elif [ -f "$i" ]; then
echo file $i
if [ $cur_fol != $main_pwd ]; then
file_list+=$i'\n'
cnt=$((cnt + 1))
fi
fi
done
}
echo "Base path: $path"
loop_folder_recurse $path
How can I modify my script to produce the desired output?
This bash script produces the output that you want:
#!/bin/bash
bigfile="$PWD/BigList"
shortfile="$PWD/ShortList"
shopt -s nullglob
loop_folder_recurse() {
(
[[ -n "$1" ]] && cd "$1"
for i in */; do
[[ -d "$i" ]] && loop_folder_recurse "$i"
count=0
files=''
for j in *; do
if [[ -f "$j" ]]; then
files+="$j"$'\n'
((++count))
fi
done
if ((count > 10)); then
outfile="$bigfile"
else
outfile="$shortfile"
fi
echo "$i" >> "$outfile"
echo "$files" >> "$outfile"
done
)
}
loop_folder_recurse
Explanation
shopt -s nullglob is used so that when a directory is empty, the loop will not run. The body of the function is within ( ) so that it runs within a subshell. This is for convenience, as it means that the function returns to the previous directory when the subshell exits.
Hopefully the rest of the script is fairly self-explanatory but if not, please let me know and I will be happy to provide additional explanation.
This checks if a file exists:
#!/bin/bash
FILE=$1
if [ -f $FILE ]; then
echo "File $FILE exists."
else
echo "File $FILE does not exist."
fi
How do I only check if the file does not exist?
The test command (written as [ here) has a "not" logical operator, ! (exclamation mark):
if [ ! -f /tmp/foo.txt ]; then
echo "File not found!"
fi
Bash File Testing
-b filename - Block special file
-c filename - Special character file
-d directoryname - Check for directory Existence
-e filename - Check for file existence, regardless of type (node, directory, socket, etc.)
-f filename - Check for regular file existence not a directory
-G filename - Check if file exists and is owned by effective group ID
-G filename set-group-id - True if file exists and is set-group-id
-k filename - Sticky bit
-L filename - Symbolic link
-O filename - True if file exists and is owned by the effective user id
-r filename - Check if file is a readable
-S filename - Check if file is socket
-s filename - Check if file is nonzero size
-u filename - Check if file set-user-id bit is set
-w filename - Check if file is writable
-x filename - Check if file is executable
How to use:
#!/bin/bash
file=./file
if [ -e "$file" ]; then
echo "File exists"
else
echo "File does not exist"
fi
A test expression can be negated by using the ! operator
#!/bin/bash
file=./file
if [ ! -e "$file" ]; then
echo "File does not exist"
else
echo "File exists"
fi
Negate the expression inside test (for which [ is an alias) using !:
#!/bin/bash
FILE=$1
if [ ! -f "$FILE" ]
then
echo "File $FILE does not exist"
fi
The relevant man page is man test or, equivalently, man [ -- or help test or help [ for the built-in bash command.
Alternatively (less commonly used) you can negate the result of test using:
if ! [ -f "$FILE" ]
then
echo "File $FILE does not exist"
fi
That syntax is described in "man 1 bash" in sections "Pipelines" and "Compound Commands".
[[ -f $FILE ]] || printf '%s does not exist!\n' "$FILE"
Also, it's possible that the file is a broken symbolic link, or a non-regular file, like e.g. a socket, device or fifo. For example, to add a check for broken symlinks:
if [[ ! -f $FILE ]]; then
if [[ -L $FILE ]]; then
printf '%s is a broken symlink!\n' "$FILE"
else
printf '%s does not exist!\n' "$FILE"
fi
fi
It's worth mentioning that if you need to execute a single command you can abbreviate
if [ ! -f "$file" ]; then
echo "$file"
fi
to
test -f "$file" || echo "$file"
or
[ -f "$file" ] || echo "$file"
I prefer to do the following one-liner, in POSIX shell compatible format:
$ [ -f "/$DIR/$FILE" ] || echo "$FILE NOT FOUND"
$ [ -f "/$DIR/$FILE" ] && echo "$FILE FOUND"
For a couple of commands, like I would do in a script:
$ [ -f "/$DIR/$FILE" ] || { echo "$FILE NOT FOUND" ; exit 1 ;}
Once I started doing this, I rarely use the fully typed syntax anymore!!
To test file existence, the parameter can be any one of the following:
-e: Returns true if file exists (regular file, directory, or symlink)
-f: Returns true if file exists and is a regular file
-d: Returns true if file exists and is a directory
-h: Returns true if file exists and is a symlink
All the tests below apply to regular files, directories, and symlinks:
-r: Returns true if file exists and is readable
-w: Returns true if file exists and is writable
-x: Returns true if file exists and is executable
-s: Returns true if file exists and has a size > 0
Example script:
#!/bin/bash
FILE=$1
if [ -f "$FILE" ]; then
echo "File $FILE exists"
else
echo "File $FILE does not exist"
fi
You can do this:
[[ ! -f "$FILE" ]] && echo "File doesn't exist"
or
if [[ ! -f "$FILE" ]]; then
echo "File doesn't exist"
fi
If you want to check for file and folder both, then use -e option instead of -f. -e returns true for regular files, directories, socket, character special files, block special files etc.
You should be careful about running test for an unquoted variable, because it might produce unexpected results:
$ [ -f ]
$ echo $?
0
$ [ -f "" ]
$ echo $?
1
The recommendation is usually to have the tested variable surrounded by double quotation marks:
#!/bin/sh
FILE=$1
if [ ! -f "$FILE" ]
then
echo "File $FILE does not exist."
fi
In
[ -f "$file" ]
the [ command does a stat() (not lstat()) system call on the path stored in $file and returns true if that system call succeeds and the type of the file as returned by stat() is "regular".
So if [ -f "$file" ] returns true, you can tell the file does exist and is a regular file or a symlink eventually resolving to a regular file (or at least it was at the time of the stat()).
However if it returns false (or if [ ! -f "$file" ] or ! [ -f "$file" ] return true), there are many different possibilities:
the file doesn't exist
the file exists but is not a regular file (could be a device, fifo, directory, socket...)
the file exists but you don't have search permission to the parent directory
the file exists but that path to access it is too long
the file is a symlink to a regular file, but you don't have search permission to some of the directories involved in the resolution of the symlink.
... any other reason why the stat() system call may fail.
In short, it should be:
if [ -f "$file" ]; then
printf '"%s" is a path to a regular file or symlink to regular file\n' "$file"
elif [ -e "$file" ]; then
printf '"%s" exists but is not a regular file\n' "$file"
elif [ -L "$file" ]; then
printf '"%s" exists, is a symlink but I cannot tell if it eventually resolves to an actual file, regular or not\n' "$file"
else
printf 'I cannot tell if "%s" exists, let alone whether it is a regular file or not\n' "$file"
fi
To know for sure that the file doesn't exist, we'd need the stat() system call to return with an error code of ENOENT (ENOTDIR tells us one of the path components is not a directory is another case where we can tell the file doesn't exist by that path). Unfortunately the [ command doesn't let us know that. It will return false whether the error code is ENOENT, EACCESS (permission denied), ENAMETOOLONG or anything else.
The [ -e "$file" ] test can also be done with ls -Ld -- "$file" > /dev/null. In that case, ls will tell you why the stat() failed, though the information can't easily be used programmatically:
$ file=/var/spool/cron/crontabs/root
$ if [ ! -e "$file" ]; then echo does not exist; fi
does not exist
$ if ! ls -Ld -- "$file" > /dev/null; then echo stat failed; fi
ls: cannot access '/var/spool/cron/crontabs/root': Permission denied
stat failed
At least ls tells me it's not because the file doesn't exist that it fails. It's because it can't tell whether the file exists or not. The [ command just ignored the problem.
With the zsh shell, you can query the error code with the $ERRNO special variable after the failing [ command, and decode that number using the $errnos special array in the zsh/system module:
zmodload zsh/system
ERRNO=0
if [ ! -f "$file" ]; then
err=$ERRNO
case $errnos[err] in
("") echo exists, not a regular file;;
(ENOENT|ENOTDIR)
if [ -L "$file" ]; then
echo broken link
else
echo does not exist
fi;;
(*) syserror -p "can't tell: " "$err"
esac
fi
(beware the $errnos support was broken with some versions of zsh when built with recent versions of gcc).
There are three distinct ways to do this:
Negate the exit status with bash (no other answer has said this):
if ! [ -e "$file" ]; then
echo "file does not exist"
fi
Or:
! [ -e "$file" ] && echo "file does not exist"
Negate the test inside the test command [ (that is the way most answers before have presented):
if [ ! -e "$file" ]; then
echo "file does not exist"
fi
Or:
[ ! -e "$file" ] && echo "file does not exist"
Act on the result of the test being negative (|| instead of &&):
Only:
[ -e "$file" ] || echo "file does not exist"
This looks silly (IMO), don't use it unless your code has to be portable to the Bourne shell (like the /bin/sh of Solaris 10 or earlier) that lacked the pipeline negation operator (!):
if [ -e "$file" ]; then
:
else
echo "file does not exist"
fi
envfile=.env
if [ ! -f "$envfile" ]
then
echo "$envfile does not exist"
exit 1
fi
To reverse a test, use "!".
That is equivalent to the "not" logical operator in other languages. Try this:
if [ ! -f /tmp/foo.txt ];
then
echo "File not found!"
fi
Or written in a slightly different way:
if [ ! -f /tmp/foo.txt ]
then echo "File not found!"
fi
Or you could use:
if ! [ -f /tmp/foo.txt ]
then echo "File not found!"
fi
Or, presing all together:
if ! [ -f /tmp/foo.txt ]; then echo "File not found!"; fi
Which may be written (using then "and" operator: &&) as:
[ ! -f /tmp/foo.txt ] && echo "File not found!"
Which looks shorter like this:
[ -f /tmp/foo.txt ] || echo "File not found!"
The test thing may count too. It worked for me (based on Bash Shell: Check File Exists or Not):
test -e FILENAME && echo "File exists" || echo "File doesn't exist"
This code also working .
#!/bin/bash
FILE=$1
if [ -f $FILE ]; then
echo "File '$FILE' Exists"
else
echo "The File '$FILE' Does Not Exist"
fi
The simplest way
FILE=$1
[ ! -e "${FILE}" ] && echo "does not exist" || echo "exists"
This shell script also works for finding a file in a directory:
echo "enter file"
read -r a
if [ -s /home/trainee02/"$a" ]
then
echo "yes. file is there."
else
echo "sorry. file is not there."
fi
sometimes it may be handy to use && and || operators.
Like in (if you have command "test"):
test -b $FILE && echo File not there!
or
test -b $FILE || echo File there!
If you want to use test instead of [], then you can use ! to get the negation:
if ! test "$FILE"; then
echo "does not exist"
fi
You can also group multiple commands in the one liner
[ -f "filename" ] || ( echo test1 && echo test2 && echo test3 )
or
[ -f "filename" ] || { echo test1 && echo test2 && echo test3 ;}
If filename doesn't exit, the output will be
test1
test2
test3
Note: ( ... ) runs in a subshell, { ... ;} runs in the same shell.