Shell Programming and Scripting

awk and sed can process entire files with millions of lines(and will beat the pants off the shell in comparison when doing so). But like any other external programs they take time to load, run, and quit. awk in particular is an entire programming language probably capable of replacing most of that script with one call.

When the amount of work being done is miniscule, the script will be wasting more time loading and quitting external programs than doing actual work. It's better to use shell builtins to process single lines of text in the shell whenever possible. The read builtin can split on tokens. Many shells have string operations which let you do regex-like replacements inside strings without calling sed. And so forth.

How to do so depends on what your shell is and what your program looks like.

I see. Which bash builitin would be good to use in this case?

---------- Post updated at 04:00 PM ---------- Previous update was at 03:58 PM ----------

would cat work?

Code:

IFS="," read G BARCODE_ID G <<<"${BARCODE_LINE}"

would work in bash, except you could probably replace whatever set BARCODE_LINE in the first place, to extract all the tokens in the line in one go, letting you remove that line and perhaps several others too.

And perhaps simplify where that variable comes from, and lines related before it, and on and on. If that habit's there, it's likely to be all over, and large parts of the script could be simplified and reduced. We'd need to see more of the script.

'cat' is almost never the answer. See Useless Use of Cat.

I'm not allowed to give it out. sorry Thanks for the information.

To illustrate further, one would be to use variable expansion in post 1:

Code:

PPLUGIN_OUT_SFF_NAME=${TSP_FILEPATH_SFF##*/}

which could replace that line, and as Corona688 so eloquently explained, would be far more effective, so the script would run faster.

or with the second example:

Code:

tmpvar=${BARCODE_LINE#*,}
BARCODE_ID=${tmpvar%%,*}

--
The example in post #1 contains an error by the way, because there should not be spaces around variable assignments, but they probably are not there in the script itself, or it would not work. And the semicolon is superfluous, and there should be double quotes around the variable expansion after echo, or it will break on directories with spaces and printf would be better to use instead of echo, or it may break with certain escape codes, depending on what echo is being used, and it is better to use $( .. ) instead of backticks )

so

Code:

PLUGIN_OUT_SFF_NAME=$(printf "%s" "${TSP_FILEPATH_SFF}" | sed 's_.*/__g')

But variable expansion is better.