The idea is that those three lines do 3 different things if they’re evaluated in a standard Bourne shell (sh), a C shell (csh), or Perl. This hack is only needed on systems that don’t support specifying an interpreter name using a #! line at the start of a script. If you execute a Perl … Read more
In your ~/.bashrc (or the first of ~/.bash_profile, ~/.bash_login, and ~/.profile that exists) source this script using something like . ~/bin/sourcecsh: #!/bin/bash # This should be sourced rather than executed while read cmd var val do if [[ $cmd == “setenv” ]] then eval “export $var=$val” fi done < ~/.cshrc This version eliminates the evil … Read more
The csh shell has never been known for its extensive ability to manipulate file handles in the redirection process. You can redirect both standard output and error to a file with: xxx >& filename but that’s not quite what you were after, redirecting standard error to the current standard output. However, if your underlying operating … Read more
With awk: awk ‘{for(i=1;i<=NF;i++) if ($i==”–pe_cnt”) print $(i+1)}’ inputFile Basically loop over each word of the line. When you find the first you are looking for, grab the next word and print it. With grep: grep -oP “(?<=–pe_cnt )[^ ]+” inputFile
sed can use any separator instead of / in the s command. Just use something that is not encountered in your paths: s+AAA+BBB+ and so on. Alternatively (and if you don’t want to guess), you can pre-process your path with sed to escape the slashes: pwdesc=$(echo $PWD | sed ‘s_/_\\/_g’) and then do what you … Read more
Try with: xargs –show-limits </dev/null Your environment variables take up 2446 bytes POSIX upper limit on argument length (this system): 2092658 POSIX smallest allowable upper limit on argument length (all systems): 4096 Maximum length of command we could actually use: 2090212 Size of command buffer we are actually using: 131072 There is no limit per … Read more
Im surprised no one used the tr “:” “\n” | grep -x techique to search if a given folder already exists in $PATH. Any reason not to? In 1 line: if ! $(echo “$PATH” | tr “:” “\n” | grep -qx “$dir”) ; then PATH=$PATH:$dir ; fi Here is a function ive made myself to … Read more
It does affect, at least bash in my environment, but in very unpleasant way. See these codes. First a.sh: #!/bin/sh echo “First echo” read y echo “$y” echo “That’s all.” b.sh: #!/bin/sh echo “First echo” read y echo “Inserted” echo “$y” # echo “That’s all.” Do $ cp a.sh run.sh $ ./run.sh $ # open … Read more
I have good experience with the following code. It doesn’t require any special user permissions: import resource, sys resource.setrlimit(resource.RLIMIT_STACK, (2**29,-1)) sys.setrecursionlimit(10**6) It does however not seem to work with pypy. If resource.setrlimit doesn’t work, you can also try using threads: sys.setrecursionlimit(10**6) import threading threading.stack_size(2**26) threading.Thread(target=main).start()
There are three approaches to finding the name of the current shell’s executable: Please note that all three approaches can be fooled if the executable of the shell is /bin/sh, but it’s really a renamed bash, for example (which frequently happens). Thus your second question of whether ps output will do is answered with “not … Read more