Linux – How to print contents instead of file name from using linux find command

catfindlinux

I have thousands of unl files named something like this cbs_cdr_vou_20180624_603_126_239457.unl. I wanted to print all the lines from those files by using following command. but its giving me only file names. I don't need file names, I just need contents from those files.

find -type f -name 'cbs_cdr_vou_20180615*.unl'  > /home/fifa/cbs/test.txt

Current Output:

./cbs_cdr_vou_20180615_603_129_152023.unl
./cbs_cdr_vou_20180615_603_128_219001.unl
./cbs_cdr_vou_20180615_602_113_215712.unl
./cbs_cdr_vou_20180615_602_120_160466.unl
./cbs_cdr_vou_20180615_603_125_174428.unl
./cbs_cdr_vou_20180615_601_101_152369.unl
./cbs_cdr_vou_20180615_603_133_193306.unl

Expected output:

8801865252020|200200|20180613100325|;
8801837463298|200200|20180613111209|;
8801845136955|200200|20180613133708|;
8801845205889|200200|20180613141140|;
8801837612072|200200|20180613141525|;
8801877103875|200200|20180613183008|;
8801877167964|200200|20180613191607|;
8801845437651|200200|20180613200415|;
8801845437651|200200|20180613221625|;
8801839460670|200200|20180613235936|;

Please note that, for cat command I'm getting error like -bash: /bin/logger: Argument list too long that's why wanted to use find instead of cat command.

Best Answer

The find utility deals with pathnames. If no specific action is mentioned in the find command for the found pathnames, the default action is to output them.

You may perform an action on the found pathnames, such as running cat, by adding -exec to the find command:

find . -type f -name 'cbs_cdr_vou_20180615*.unl' -exec cat {} + >/home/fifa/cbs/test.txt

This would find all regular files in or under the current directory, whose names match the given pattern. For as large batches of these as possible, cat would be called to concatenate the contents of the files.

The output would go to /home/fifa/cbs/test.txt.

Understanding the -exec option of `find`

Related Solutions

Command that prints file contents given filename on stdin

After doing a bit more research I realised that this scenario is exactly what xargs is designed for:

./my-command args | cut -d : -f 5 | xargs cat

Which will transform the output of stdin into an invocation of cat with an actual filename and thus print out the file contents

Shell – /bin/cat: Argument list too long

If you want a line-count for each individual file:

find . -type f -exec wc -l {} + | awk '! /^[ 0-9]+[[:space:]]+total$/'

I've excluded the total lines because there will be several of them with this many files being processed. The find ... -exec ... + will try to fit as many filenames onto a single command line as possible, but that will be a LOT less than 119766 files....probably only several thousand (at most) per invocation of wc, and each one will result in its own independent 'total' line.

If you want the total number of lines in all files combined, here's one way of doing it:

find . -type f -exec wc -l {} + | 
    awk '/^[ 0-9]+[[:space:]]+total$/ {print $1}' | 
    xargs | sed -e 's/ /+/g' | bc

This prints only the line counts on the total lines, pipes that into xargs to get the counts all on one line, then sed to transform the spaces into + signs, and then pipes the lot into bc to do the calculation.

Example output:

$ cd /usr/share/doc
$ find . -type f -exec wc -l {} + | 
    awk '/^[ 0-9]+[[:space:]]+total$/ {print $1}' | 
    xargs | sed -e 's/ /+/g' | bc 
53358931

Best Answer

Related Solutions

Command that prints file contents given filename on stdin

Shell – /bin/cat: Argument list too long

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