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Under the folder /usr/hdp/2.6.4.0-91/tez_hive2/lib/
We have .jar files as the following

$ ls  /usr/hdp/2.6.4.0-91/tez_hive2/lib/ | grep ".jar"

async-http-client-1.8.16.jar

azure-data-lake-store-sdk-2.1.4.jar

commons-cli-1.2.jar

commons-codec-1.4.jar

commons-collections-3.2.2.jar

commons-collections4-4.1.jar

commons-io-2.4.jar

commons-lang-2.6.jar

commons-math3-3.1.1.jar

guava-11.0.2.jar

hadoop-aws-2.7.3.2.6.4.0-91.jar

hadoop-azure-2.7.3.2.6.4.0-91.jar

hadoop-azure-datalake-2.7.3.2.6.4.0-91.jar

hadoop-mapreduce-client-common-2.7.3.2.6.4.0-91.jar

hadoop-mapreduce-client-core-2.7.3.2.6.4.0-91.jar

hadoop-yarn-server-timeline-pluginstorage-2.7.3.2.6.4.0-91.jar

jersey-client-1.9.jar

jersey-json-1.9.jar

jettison-1.3.4.jar

jetty-6.1.26.hwx.jar

jetty-util-6.1.26.hwx.jar

jsr305-3.0.0.jar

metrics-core-3.1.0.jar

protobuf-java-2.5.0.jar

RoaringBitmap-0.4.9.jar

servlet-api-2.5.jar

slf4j-api-1.7.10.jar

I want to count all characters from the .jar files by wc , in order to understand if .jar files renamed

So I do the following command in order to count all characters from all .jar files

ls  /usr/hdp/2.6.4.0-91/tez_hive2/lib/ | grep ".jar" | sed s'/// /g' | awk '{print $NF}' | wc | awk '{print $NF}'

758

So in this case we get 758 characters from all .jars

But the command isn’t elegant

How we can improve the command to be better?

Most probably you are looking for

basename -a /usr/hdp/2.6.4.0-91/tez_hive2/lib/*.jar | wc -c

The path with wildcard list all jar files, the basename command strips directories (-a is needed to accept many arguments), and wc -c just counts bytes (if some filenames consist of 2 byte characters then perhaps wc -m (characters count) would be a better choice).

However, to if the goal is to check if files have been modified then perhaps stat (for modification time) or md5sum/shasum for checksum would be a better tools.

Counting the number of letters in the filenames would not be a safe way of detecting a renamed filename.

Instead, create a simple file listing of the names, and compare it to an existing list. By using diff, you would be shown exactly which line(s) in the list had changed.

#!/bin/sh



LC_ALL=C



newlist=$HOME/filelist.new

oldlist=$HOME/filelist.old



echo /usr/hdp/2.6.4.0-91/tez_hive2/lib/*.jar >"$newlist"



if [ -f "$oldlist" ]; then

    diff -u "$oldlist" "$newlist"

fi



mv "$newlist" "$oldlist"

Obviously, the first time you do this, filelist.old would not exist, so the diff would not run.

Note that I save the full path to each file in the output file. This does not matter since the directory path is static.

Change echo to ls -l if you want to also compare timestamps etc. Change it to stat if you want to compare even more meta data (this would generate diff output when even the last-access timestamp on a file changed). Install wdiff and change diff to wdiff to get a word-based diff rather than a line-based one.

The LC_ALL=C is to guarantee a consistent sorting of the expansion of the shell glob.

To just get the number of characters in the (non-hidden) jar filenames, I would do

cd /usr/hdp/2.6.4.0-91/tez_hive2/lib/ && printf %s *.jar | wc -m

This will not count any newlines, just the filename characters (replace wc -m with wc -c for the number of bytes instead of characters).

Purposefully, I'm not parsing ls output.

I don't understand the point of the sed command, you are replacing a slash with a space? Why?

Aside from that, it seems that you want to count the total number of characters in all the file names of the .jar files. IF so, try this:
ls /usr/hdp/2.6.4.0-91/tez_hive2/lib/*.jar | sed s'/// /g' | wc -c

Two other possibilities for your sed command:
sed "s|/| |g" -- or -- tr '/' ' '

Since your ls command won't show directory names, I am not sure you need it.

This will also count the LF at the end of each file name. Is that OK?