General rule: quote it if it can either be empty or contain spaces (or any whitespace really) or special characters (wildcards). Not quoting strings with spaces often leads to the shell breaking apart a single argument into many. $? doesn’t need quotes since it’s a numeric value. Whether $URL needs it depends on what you … Read more
You could try a combination of strptime and mktime struct tm tm; time_t epoch; if ( strptime(timestamp, “%Y-%m-%d %H:%M:%S”, &tm) != NULL ) epoch = mktime(&tm); else // badness
It’s the man page section. From memory, section 1 is user programs, 2 is system calls, and 3 is standard C library calls, and 5 is file formats. Wikipedia has the full explanation here.
From fork(2): * The child inherits copies of the parent’s set of open file descrip- tors. Each file descriptor in the child refers to the same open file description (see open(2)) as the corresponding file descriptor in the parent. This means that the two descriptors share open file status flags, current file offset, and signal-driven … Read more
Addressing the proposed solution from dmckee: While some versions of Bash may allow hyphens in function names, others (MacOS X) do not. I don’t see a need to use return immediately before the end of the function. I don’t see the need for all the semi-colons. I don’t see why you have path-element-by-pattern export a … Read more
Simply don’t put whole commands in variables. You’ll get into a lot of trouble trying to recover quoted arguments. Also: Avoid using all-capitals variable names in scripts. It is an easy way to shoot yourself in the foot. Don’t use backquotes. Use $(…) instead; it nests better. #! /bin/bash if [ $# -ne 2 ] … Read more
No, it is not ok. All commands in a pipeline execute at the same time, and the shell prepares redirections before executing the commands. So, it is likely that the command will overwrite the file before cat reads it. You need sponge(1) from moreutils.
I have that in my gist. I created a stl wrapper around glob so that it returns vector of string and take care of freeing glob result. Not exactly very efficient but this code is a little more readable and some would say easier to use. #include <glob.h> // glob(), globfree() #include <string.h> // memset() … Read more
Since you tagged this “gcc”, try #if __x86_64__ /* 64-bit */ #endif
I don’t know if it’s possible to do ranges in awk. You could do a for loop, but you would have to add handling to filter out the columns you don’t want. It’s probably easier to do this: awk -F, ‘{OFS=”,”;print $1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$20,$21,$22,$23,$24,$25,$30,$33}’ infile.csv > outfile.csv something else to consider – and this faster and more … Read more