This is how environment variables work. Every process has a copy of the environment. Any changes that the process makes to its copy propagate to the process’s children. They do not, however, propagate to the process’s parent. One way to get around this is by using the source command: source ./test.sh or . ./test.sh (the … Read more
grep -e ‘attrib1’ -e ‘attrib3’ file From the man page : -e PATTERN, –regexp=PATTERN Use PATTERN as the pattern. This can be used to specify multiple search patterns, or to protect a pattern beginning with a hyphen (-). (-e is specified by POSIX.) Edit : Alternatively , you can save patterns in a file and … Read more
Find only regular files under current directory, and print them without “./” prefix: find -type f -printf ‘%P\n’ From man find, description of -printf format: %P File’s name with the name of the command line argument under which it was found removed.
Try gnuplot. It has very powerful graphing possibilities. It can output to your terminal in the following way: gnuplot> set terminal dumb Terminal type set to ‘dumb’ Options are ‘feed 79 24’ gnuplot> plot sin(x) 1 ++—————-**—————+—-**———–+——–**—–++ + *+ * + * * + sin(x) ****** + 0.8 ++ * * * * * * … Read more
Unix uses 0xA for a newline character. Windows uses a combination of two characters: 0xD 0xA. 0xD is the carriage return character. ^M happens to be the way vim displays 0xD (0x0D = 13, M is the 13th letter in the English alphabet). You can remove all the ^M characters by running the following: :%s/^M//g … Read more
. name sources the file called name into the current shell. So if a file contains this A=hello Then if you sources that, afterwards you can refer to a variable called A which will contain hello. But if you execute the file (given proper execution rights and #!/interpreterline), then such things won’t work, since the … Read more
awk ‘FNR==1 && NR!=1{next;}{print}’ *.csv tested on solaris unix: > cat file1.csv Id,city,name ,location 1,NA,JACK,CA > > cat file2.csv ID,city,name,location 2,NY,JERRY,NY > > nawk ‘FNR==1 && NR!=1{next;}{print}’ *.csv Id,city,name ,location 1,NA,JACK,CA 2,NY,JERRY,NY > Explanation given by kevin-d: FNR is the number of lines (records) read so far in the current file. NR is the number … Read more
Tried printf(1)? printf “%x\n” 34 22 There are probably ways of doing that with builtin functions in all shells but it would be less portable. I’ve not checked the POSIX sh specs to see whether it has such capabilities.
an example $ echo “something” | mailx -s “subject” [email protected] to send attachment $ uuencode file file | mailx -s “subject” [email protected] and to send attachment AND write the message body $ (echo “something\n” ; uuencode file file) | mailx -s “subject” [email protected]
The ‘c’ means it’s a character device. tty is a special file representing the ‘controlling terminal’ for the current process. Character Devices Unix supports ‘device files’, which aren’t really files at all, but file-like access points to hardware devices. A ‘character’ device is one which is interfaced byte-by-byte (as opposed to buffered IO). TTY /dev/tty … Read more