In bash scripts (non-interactive) by default JOB CONTROL is disabled so you can’t do the the commands: job, fg, and bg. Here is what works well for me: #!/bin/sh set -m # Enable Job Control for i in `seq 30`; do # start 30 jobs in parallel sleep 3 & done # Wait for all …
The question does not contain a nested loop, just a single loop. But THIS nested version works, too: # for i in c d; do for j in a b; do echo $i $j; done; done c a c b d a d b
A wild stab in the dark for modifying a single value: sed -c -i “s/\($TARGET_KEY *= *\).*/\1$REPLACEMENT_VALUE/” $CONFIG_FILE assuming that the target key and replacement value don’t contain any special regex characters, and that your key-value separator is “=”. Note, the -c option is system dependent and you may need to omit it for sed …
As other people explained, getopts doesn’t parse long options. You can use getopt, but it’s not portable (and it is broken on some platform…) As a workaround, you can implement a shell loop. Here an example that transforms long options to short ones before using the standard getopts command (it’s simpler in my opinion): # …
Tip of the hat to @gniourf_gniourf and @chepner for their help. tl;dr To be safe, double-quote: it’ll work in all cases, across all POSIX-like shells. If you want to add a ~-based path, selectively leave the ~/ unquoted to ensure that ~ is expanded; e.g.: export PATH=~/”bin:$PATH”. See below for the rules of ~ expansion …
I am assuming these scripts are running in two different processes, i.e. you are not “sourcing” one of them. It depends on what you want to return. If you wish only to return an exit code between 0 and 255 then: # Child (for example: ‘child_script’) exit 42 # Parent child_script retn_code=$? If you wish …
find . -size +10000k -exec ls -sd {} + If your version of find won’t accept the + notation (which acts rather like xargs does), then you might use (GNU find and xargs, so find probably supports + anyway): find . -size +10000k -print0 | xargs -0 ls -sd or you might replace the + …
Try: read -e -p “Glassfish Path:” GF_DIR -e enables readline: -e If the standard input is coming from a terminal, Readline is used to obtain the line.
It’s because in your first case, your current shell expands the $HELLO variable before running the commands. And there’s no HELLO variable set in your current shell. env HELLO=’Hello World’ echo $HELLO will do this: expand any variables given, in this case $HELLO run env with the 3 arguments ‘HELLO=Hello World’, ‘echo’ and ” (an …
Use – to left align a field. printf “Echoing random number %-5s [ OK ]” $RAND_NUM Alternatively, if you’re on a Red Hat Linux system there are predefined functions that will print out green OK and red FAILED prompts (the ones you see during bootup): #!/bin/bash . /etc/init.d/functions echo -n “Frobbing widget:” frob_widget && echo_success …