I have file which does not have any data in it
Need to check below scenario and return file is empty otherwise not empty
if file contains no data but as only spaces return it as FILE is EMPTY
if file contains no data but as only tabs return it as FILE is EMPTY
if file contains no data but as only empty new line return it as FILE is EMPTY
Does this below code will satisfy all my above cases ? or any best approach all in one go
if [ -s /d/dem.txt ]
then
echo "FILE IS NOT EMPTY AS SOME DATA"
else
echo "FILE IS EMPTY NOT DATA AVAILABLE"
fi
You may use this awk for this:
awk 'NF {exit 1}' file && echo "empty" || echo "not empty"
Condition NF will be true only if there is non-whitespace character in the file.
Your description is a bit unclear (what do you want to do with a file that contains spaces, tabs, and newlines?), but it sounds like you just want to know if the file contains any non-whitespace characters. So:
if grep -q '[^[:space:]]' "$file"; then
printf "%s\n" "$file is not empty";
else
printf "%s\n" "$file contains only whitespace"
fi
If you had run your code you would have realized that no, -s considers that files with spaces, tabs and/or new lines are not empty. I would do it like this:
myfile="some_file.txt"
T=$(sed -e 's/\s//g' "$i")
if [ -n "$T" ]; then
echo "$i is NOT empty"
else
echo "$i is empty"
fi
Related
I am trying to say, if document does not exist, then create document. Next read each line of the document and if none of the lines match the $site/$name variables, then add the $site/$name variable into the document.
#!/bin/bash
site=http://example.com
doc=$HOME/myfile.txt
if [ ! -f $doc ]
then
touch $doc
fi
read -p "name? " name
while read lines
do
if [[ $lines != $site/$name ]]
then
echo $site/$name >> $doc
fi
done <$doc
echo $doc
echo $site
echo $name
echo $site/$name
echo $lines
Typing test at the read -p prompt the results are
path/to/myfile.txt
http://example.com
test
http://example.com/test
I feel like I should know this but I'm just not seeing it. What am I doing wrong?
If the file is initially empty, you'll never enter the loop, and thus never add the line. If the file is not empty, you'd add your line once for every non-matching line anyway. Try this: set a flag to indicate whether or not to add the line, then read through the file. If you ever find a matching line, clear the flag to prevent the line from being added after the loop.
do_it=true
while read lines
do
if [[ $lines = $site/$name ]]
then
do_it=false
break
fi
done < "$doc"
if [[ $do_it = true ]]; then
echo "$site/$name" >> "$doc"
fi
The following creates the file if it doesn't exist. It then checks to see if it contains $site/$name. If it doesn't find it, it adds the string to the end of the file:
#!/bin/bash
site=http://example.com
doc=$HOME/myfile.txt
read -p "name? " name
touch "$doc"
grep -q "$site/$name" "$doc" || echo "$site/$name" >>"$doc"
How it works
touch "$doc"
This creates the file if it doesn't exist. If it does already exist, the only side-effect of running this command is that the file's timestamp is updated.
grep -q "$site/$name" || echo "$site/$name" >>"$doc"
The grep command sets its exit code to true if it finds the string. If it doesn't find it, then the "or" clause (in shell, || means logical-or) is triggered and the echo command adds the string to the end of the file.
echo "Please Enter a Forename";
read Forename;
if [ ! $Forename ]; then
echo "$Forename not found";
else
grep -n "Forename: $Forename" $Filename | sort;
fi
I am trying to use the above code to check if a string the user enters is present in a file, the file name is AddressBook.txt which I have assigned to the variable Filename.
Can anyone advise me whether this would work or could you suggest a better way to check the file.
You can print the contents of a file using cat for instance:
contents=$( cat $filename )
Now you can check if the string contents is empty:
if [ -n "$contents" ]; then
echo "The contents of the file are empty"
fi
You can use grep to check for a particular string:
contents=$( grep "$pattern" "$filename" )
And from here on the if will be the same.
I have two files one of them have that data file1:
content
file2 is created with vi and I just put some enters and have two or three rows but still no data just content.
That is not working for me, when have rows added but no other thing.
if [ ! -s file2 ]
print "file2 is empty"
else
print "file2 has content"
fi
In that case is turn: file2 has content
The idea is to catch in that file if there any alphabet or number anything else like space or enter to be empty.
if perl -ne'exit 1 if /\S/' file ; then
echo 'Only contains blank lines'
fi
Come to think of it, grep would also do the trick.
if ! grep -q '[^[:space:]]' file ; then
echo 'Only contains blank lines'
fi
These are better than anubhava's solution because they consider lines containing only spaces and tabs to be blank lines. It's never a good idea to assign significance to trailing whitespace.
You can use $(<file2) instead to check zero-content file:
if [[ -z "$(<file2)" ]]; then
print "file2 is empty"
else
print "file2 has content"
fi
[[ -z "$(<file2)" ]] will only be true for zero content file or a file with only new lines,
awk way
awk 'NF{x++}END{print x?"File has content":"File empty"}' file
You could also stop processing the file when content is found this way
awk 'x+=NF{exit}END{print x?"File has content":"File empty"}' file
I'm trying to fix a bash script by adding in some error catching. I have a file (list.txt) that normally has content like this:
People found by location:
person: john [texas]
more info on john
Sometimes that file gets corrupted, and it only has that first line:
People found by location:
I'm trying to find a method to check that file to see if any data exists on line 2, and I want to include it in my bash script. Is this possible?
Simple and clean:
if test $(sed -n 2p < /path/to/file); then
# line 2 exists and it is not blank
else
# otherwise...
fi
With sed we extract the second line only. The test expression will evaluate to true only if there is a second non-blank line in the file.
I assume that you want to check whether line 2 of a given file contains any data or not.
[ "$(sed -n '2p' inputfile)" != "" ] && echo "Something present on line 2" || echo "Line 2 blank"
This would work even if the inputfile has just one line.
If you simply want to check whether the inputfile has one line or more, you can say:
[ "$(sed -n '$=' z)" == "1" ] && echo "Only one line" || echo "More than one line"
Sounds like you want to check if your file has more than 1 line
if (( $(wc -l < filename) > 1 )); then
echo I have a 2nd line
fi
Another approach which doesn't require external commands is:
if ( IFS=; read && read -r && [[ -n $REPLY ]]; ) < /path/to/file; then
echo true
else
echo false
fi
How come the additional 'Line' insideecho "Line $line" is not prepended to all files inside the for loop?
#!/bin/bash
INPUT=targets.csv
IFS=","
[ ! -f $INPUT ] && { echo "$INPUT file not found"; exit 99; }
while read target user password path
do
result=$(sshpass -p "$password" ssh -n "$user"#"$target" ls "$path"*file* 2>/dev/null)
if [ $? -ne 0 ]
then
echo "No Heap dumps detected."
else
echo "Found a Heap dump! Possible OOM issue detected"
for line in $result
do
echo "Line $line"
done
fi
done < $INPUT
.csv file contents ..
rob#laptop:~/scripts$ cat targets.csv
server.com,root,passw0rd,/root/
script output ..
rob#laptop:~/scripts$ ./checkForHeapdump.sh
Found a Heap dump! Possible OOM issue detected
Line file1.txt
file2.txt
The statement:
for line in $result
performs word splitting on $result to get each element that $line should be set to. Word splitting uses the delimiters in $IFS. Earlier in the script you set this to just ,. So this loop will iterate over comma-separated data in $result. Since there aren't any commas in it, it's just a single element.
If you want to split it by lines, do:
IFS="
"
for line in $result