UNIX for Beginners Questions & Answers

Hi,
I want to extract part of filename, for eg:

Code:

File="010020004_S-TOR-Sort-CASAP_20170519_121504_0007.TXT"

here i need first 5 words of file i.e.

Code:

FilePart="$(echo "${File%[-_]"${File#*[_-]*[-_]*[_-]*[_-]*[_-]*}"}")"
Echo $FilePart
010020004_S-TOR-Sort-CASAP

But what if i get filename like below:

Code:

File="010020004_S-TOR-Sort-CAS_P_20170519_121504_0007.TXT"
FilePart="$(echo "${File%[-_]"${File#*[_-]*[-_]*[_-]*[_-]*[_-]*}"}")"
Echo $FilePart
010020004_S-TOR-Sort-CAS

So in second file filename contains [_-] as seperators but "_" is present in filename itself..is there any way i can skip specific seperator and ignore if "_' is not seperator.

Kindly help me out on this
TIA

Assuming your filenames always have the _yyyymmdd_hhmmss_vvvv.TXT component and your shell is bash 4.x, try

Code:

FilePart=${File:0:-25}

or for bash 3.x:

Code:

FilePart=${File:0:(( ${#File}-25 ))}

Andrew

If you state that _ and - are word separators and you want the first 5 words from the string contained in a variable; no your code cannot reliably guess at how many separators in the first 5 words are not separators.

If you know that the part of the filename that you do not want always ends with three occurrences of _string, you could use:

Code:

File="010020004_S-TOR-Sort-CAS_P_20170519_121504_0007.TXT"
FilePart=${File%_*_*_*}
echo "$FilePart"

with any shell that performs the variable expansions required by the POSIX standards.

Note also that there is a huge difference between using the command name echo and the command name Echo in any system that conforms to the standards. Utility names are case sensitive and there is no definition in the standards as to what a command named Echo will do (if such a command exists on your system).

Also note that there is no need to use echo and command substitution in the assignment of the variable expansion.

If you know for sure that the last subitem you want has alphabetic letters, and the first you want removed has digits, try

Code:

File="010020004_S-TOR-Sort-CASAP_20170519_121504_0007.TXT"
echo ${File%_[0-9]${File#*[_-]*[_-]*[_-]*[_-]*[^A-Z_]}}
010020004_S-TOR-Sort-CASAP
File="010020004_S-TOR-Sort-CAS_P_20170519_121504_0007.TXT"
echo ${File%_[0-9]${File#*[_-]*[_-]*[_-]*[_-]*[^A-Z_]}}
010020004_S-TOR-Sort-CAS_P

If you can't rely on that structure, I'm afraid you're lost.