It is a mistake to use regular expression matching when the "patterns" to be matched are not patterns but literal strings. Consider what would happen if one of the literal strings contains a regular expression metacharacter. Perhaps that's extremely unlikely with usernames, but it should be considered.
Even if regular expression matching is disabled, there is still the problem of substring matches, since there is no anchoring in effect.
To disable both regular expression matching (in favor of fixed string matching) and (assuming one username per line) to require whole-line matching to prevent substring matches:
There is no point in sorting when using grep. Whatever is gained (when a pattern near the head of the pattern list matches one of the first lines of data) is surrendered (when later matches consistently nearly-exhaust the pattern list) and sorting overhead is never recovered.
If you are going to sort the files, comm would be a more efficient alternative.
Hi friends,
I would like to compare two dates in an IF statement.
This is what I am trying, but it doesn't work.
date=20120122
minus=6
if ; then
...
fi
what would the IF clause looks like?
Thanks! :) (5 Replies)
hi guys
i need a program that can compare a value read from a com-port and one from the terminal.
can somebody help me???
using linux kernel 2.6.14-M5
can only use standard function in sh and bash... (5 Replies)
Is there a way to compare the permission string of two files and output the string if they match?
For ex:
-rw-r--r-- 1 user newuser 0 2009-03-12 16:45 file2
-rw-r--r-- 1 user newuser 0 2009-03-12 16:46 fileone
output:
-rw-r--r--
If they don't match output will be just... (3 Replies)
I have an array @name with the below contents (index 7 and 8 are names):
1|1|2|2|I|2|0|DUNN|LACY||||||
2|2|2|2|I|2|0|KOFE|ROGER||||||
3|3|2|2|A|2|0|KOFOED|ROBERT||||||
3|4|2|2|A|2|0|KOFOED|ROBERT||||||
3|5|2|2|A|2|0|KOFOED|ROBERT||||||
2|7|2|2|I|2|0|WILLIAMSON|JAMES||||||... (4 Replies)
what is the easy way to compare checksums of sereral paramters by script:
for example:
#im creating a file containing a list of checksum parameters
cksum /opt/LGTOaam51/data_source_types/UX_File_System/* > t1
#and another one
cksum /opt/LGTOaam51/data_source_types/UX_File_System2/* > t2
... (2 Replies)
hi
I have 2 files to comapre ,in file a sible column it is numbers,in file b2 numbers and other values with coma separated.
i want compare numbers in file a with file b,and the out put put should be in C with numbers in both file a and b along with other columns of file b.
i used folowing... (7 Replies)
I need some help which would probably be for most of you a simple script.
I need to read in the data from a .dat file and then compare avg to see who is the highest avg. Here is my script so far.
#!/bin/ksh
#reading in the data from lab3.dat
filename=$1
while read name o1 o2 o3 o4 o5 o6... (0 Replies)
can anyone point me to a comparison of *nix file systems ?
i think i prefer a journalling fs
but i would like to see a comparison between several fs's before i make up my mind (2 Replies)