Print the Last Line of a File, from the Cli

Print the last line of a file, from the CLI

$ cat file | awk 'END{print}'

Originally answered by Ventero

Last line of a file is not reading in shell script

This is due to missing line break in the last line of your input file.

You can use this loop to read everything:

while IFS= read -r line || [ -n "$line" ]; do
    echo "$line"
done < "$file"

For the last line without line break, read doesn't return a success hence [ -n "$line" ] check is done to make sure to print it when $line is not empty.

PS: If you don't mind changing your input file then use printf to append a newline using:

printf '\n' >> "$file"

And then read normally:

while IFS= read -r line; do
    echo "$line"
done < "$file"

How to get the last line of a file using cat command

Don't use cat. tail was meant for this usecase exactly:

$ tail -1 ./test.properties

How to only read the last line from a text file

Use tail ;)

line=$(tail -n 1 input_file)
echo $line

Perl code to check the last line number of a file

If you want the last line number, wait to print $. until outside the while loop for processing the file:

open my $fh, '<', "$qbsid_dir/$file" or die "Can't open $file: $!";

1 while (<$fh>);
print "$file -> $.\n";

close $fh;

Be sure to read: perlfaq5 - How do I count the number of lines in a file?

Windows equivalent of the 'tail' command

No exact equivalent. However there exist a native DOS command "more" that has a +n option that will start outputting the file after the nth line:

DOS Prompt:

C:\>more +2 myfile.txt

The above command will output everything after the first 2 lines.

This is actually the inverse of Unix head:

Unix console:

root@server:~$ head -2 myfile.txt

The above command will print only the first 2 lines of the file.

how to print variables after each file with awk

Action you are looking to be done should be covered with ENDFILE, try following code once. This is a GNU awk option, should work for your shown versioned of awk.

awk -F"'" '/export const/ { CLSNM = $0 } ENDFILE{ print CLSNM;CLSNM="" }' *

2nd solution: without EBNDFILE option try following, should work with any awk version.

awk -F"'" 'FNR==1 && CLSNM{ print CLSNM; CLSNM=""} /export const/ { CLSNM = $0 } END{if(CLSNM){print CLSNM}}' *

continuously print the last line of a file Linux termin

Use the UNIX command "tail" with the -f option. That will continuously print out contents from the file to the terminal as it is added to the file.

Example:

tail -f emptyfile

You can terminate the tail process by typing Ctrl + C.

I am trying to print the last line of every file in a directory using shell command from python script

Your shell scripting is orders of magnitude too complex.

output = subprocess.check_output('tail -qn1 *', shell=True)

or if you really prefer,

os.system('tail -qn1 *')

which however does not capture the output in a Python variable.

If you have a recent-enough Python, you'll want to use subprocess.run() instead. You can also easily let Python do the enumeration of the files to avoid the pesky shell=True:

output = subprocess.check_output(['tail', '-qn1'] + os.listdir('.'))

As noted above, if you genuinely just want the output to be printed to the screen and not be available to Python, you can of course use os.system() instead, though subprocess is recommended even in the os.system() documentation because it is much more versatile and more efficient to boot (if used correctly). If you really insist on running one tail process per file (perhaps because your tail doesn't support the -q option?) you can do that too, of course:

for filename in os.listdir('.'):
    os.system("tail -n 1 '%s'" % filename)

This will still work incorrectly if you have a file name which contains a single quote. There are workarounds, but avoiding a shell is vastly preferred (so back to subprocess without shell=True and the problem of correctly coping with escaping shell metacharacters disappears because there is no shell to escape metacharacters from).

for filename in os.listdir('.'):
    print(subprocess.check_output(['tail', '-n1', filename]))

Finally, tail doesn't particularly do anything which cannot easily be done by Python itself.

for filename in os.listdir('.'):
    with open (filename, 'r') as handle:
        for line in handle:
            pass
        # print the last one only
        print(line.rstrip('\r\n'))

If you have knowledge of the expected line lengths and the files are big, maybe seek to somewhere near the end of the file, though obviously you need to know how far from the end to seek in order to be able to read all of the last line in each of the files.

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