[[ ... ]] supports everything [ ... ] does and more, it's an extended syntax. I am supposed to be getting into the habit of using [[ ... ]] all the time as pretty much mandated by standard now, but it's a hard habit to break.
No. The POSIX standards and the Single UNIX specifiations do not yet specify [[ ... ]].
Note that test and its synonym [ are (built-in) utilities, while [[ expression ]] is a part of the shell programming language (l.e., [[ is a keyword not a utility name).
A bug report (#375) was filed in February 2011 that has morphed into a proposal to include a subset of the expressions some shells support with:
syntax in the next revision of the standards. But even with the comments added last month, we still don't have a proposal that is likely to pass ballot requirements (at least 75% approval) to become part of the standards yet.
This User Gave Thanks to Don Cragun For This Post:
I have a directory that contains a number of history files for a process. Every file starts with the string "EVACK". FOr example
EVACK0101.000001
EVACK0102.095940
EVACKmmdd.hhmiss
I want to erase in the specific directory ONLY(no sub-directories) all EVACK files older then 90 days. I... (2 Replies)
Hello all
Im trying to write one liner that will show me results only if the result of the expression is greater then 0
For example:
I do :
find . -name "*.dsp" | xargs grep -c SecurityHandler
the result are :
./foo/blah/a.dsp:0
./foo/blah1/b.dsp:1
./foo/blah2/c.dsp:2... (1 Reply)
HI All,
I have a file with contents like this:
apple
computer
terminal
applecomputernetworkrouterterminalrouter
network
router
applecomputernetworkrouterterminalrouter
I want to remove all lines with length greater than "18 alphabets". Hence, my output should be:
apple
computer... (1 Reply)
Hello,
In my code I am checking to see if a variable that contains a decimal number is greater than 0 in the following manner:
if
do something
fi
However I am getting the error message (if $i for the current iteration holds 9.6352)
command 9.6352 is not found
How can I rectify... (5 Replies)
Hi all,
I have a tab-delimited text file of size 10Mb. I am trying to count the number of lines using,
grep -c . sample.txtor
wc -l < sample.txt or
awk 'END {print NR}' sample.txtAll these commands shows the count as 1, which means they are reading only the first header line of the file.... (3 Replies)
A newbie question...
I need to get a list of the Files and folders which are greater then a specific date. I want write the output to a Text file.
What I know ls -lrt gives me list of all the files ordered by date. Also ls > fileName will write the results to a text file.
Please help (6 Replies)
data:
hello mr smith 400 you all ok?
hello mrs. smith 700 you all ok?
hello mr. everyone 150 you all ok?
hello mr. you all 199 im lad you are ok
using egrep, how can i grep out only lines that have a number greater than 250?
cat data | egrep .....
can't use awk here. i was... (7 Replies)
i'm aware awk can do what i'm trying to do here. but i cant use awk in this scenario given the circumstance of this box.
but i need to check if a number is a certain column is over a certain value, say for instance, 20.
data:
| 12 | 19 | 2000 | 9029333 |... (11 Replies)
Hello,
I am newbie to bash scripting. Could someone help me with the following.
I have log file with output as shown below
**************************LOG*************************
11/20/2013 9:11:23.64 Pinging xx.xx.xx.xx with 32 bytes of data:
11/20/2013 9:11:23.64 Reply from xx.xx.xx.xx:... (4 Replies)
Discussion started by: meena_2013
4 Replies
LEARN ABOUT OPENSOLARIS
re_exec
re_comp(3C) Standard C Library Functions re_comp(3C)NAME
re_comp, re_exec - compile and execute regular expressions
SYNOPSIS
#include <re_comp.h>
char *re_comp(const char *string);
int re_exec(const char *string);
DESCRIPTION
The re_comp() function converts a regular expression string (RE) into an internal form suitable for pattern matching. The re_exec() func-
tion compares the string pointed to by the string argument with the last regular expression passed to re_comp().
If re_comp() is called with a null pointer argument, the current regular expression remains unchanged.
Strings passed to both re_comp() and re_exec() must be terminated by a null byte, and may include NEWLINE characters.
The re_comp() and re_exec() functions support simple regular expressions, which are defined on the regexp(5) manual page. The regular
expressions of the form {m}, {m,}, or {m,n} are not supported.
RETURN VALUES
The re_comp() function returns a null pointer when the string pointed to by the string argument is successfully converted. Otherwise, a
pointer to one of the following error message strings is returned:
No previous regular expression
Regular expression too long
unmatched (
missing ]
too many () pairs
unmatched )
Upon successful completion, re_exec() returns 1 if string matches the last compiled regular expression. Otherwise, re_exec() returns 0 if
string fails to match the last compiled regular expression, and -1 if the compiled regular expression is invalid (indicating an internal
error).
ERRORS
No errors are defined.
USAGE
For portability to implementations conforming to X/Open standards prior to SUS, regcomp(3C) and regexec(3C) are preferred to these func-
tions. See standards(5).
SEE ALSO grep(1), regcmp(1), regcmp(3C), regcomp(3C), regexec(3C), regexpr(3GEN), regexp(5), standards(5)SunOS 5.11 26 Feb 1997 re_comp(3C)