I suggest to replace sed “s/regex/replace/” file with sed “s|regex|replace|” file if your sed supports it. Then it is no longer necessary to escape the slashes. The character directly after the s determines which character is the separator, which must appear three times in the s command.
A bit late to the party but for the benefit of others, I found the ‘w’ flag to be exactly what I was looking for. sed -i “s/$pattern/$new_pattern/w changelog.txt” “$filename” if [ -s changelog.txt ]; then # CHANGES MADE, DO SOME STUFF HERE else # NO CHANGES MADE, DO SOME OTHER STUFF HERE fi changelog.txt … Read more
The docker shell syntax (which is just a string as the RUN, ENTRYPOINT, and CMD) will run that string as the parameter to /bin/sh -c. This gives you a shell to expand variables, sub commands, piping output, chaining commands together, and other shell conveniences. RUN ls * | grep $trigger_filename || echo file missing && … Read more
Short answer: //usr/bin/clang “$0” && exec ./a.out “$@” int main(){ return 0; } The trick is that your text file must be both valid C/C++ code and shell script. Remember to exit from the shell script before the interpreter reaches the C/C++ code, or invoke exec magic. Run with chmod +x main.c; ./main.c. A shebang … Read more
You can achieve something similar by abusing the –rcfile option: bash –rcfile <(echo “export PS1=’> ‘ && ls”) From bash manpage: –rcfile file Execute commands from file instead of the system wide initialization file /etc/bash.bashrc and the standard personal initialization file ~/.bashrc if the shell is interactive
Thanks to @jessenoller on Twitter I have an answer that fits my needs – you can compile lxml with static dependencies, hence avoiding messing with the libxml2 that ships with OS X. Here’s what worked for me: cd /tmp curl -O http://lxml.de/files/lxml-3.6.0.tgz tar -xzvf lxml-3.6.0.tgz cd lxml-3.6.0 python setup.py build –static-deps –libxml2-version=2.7.3 –libxslt-version=1.1.24 sudo python … Read more
Looks like try: # py3 from shlex import quote except ImportError: # py2 from pipes import quote quote(“hello stack overflow’s quite cool”) >>> ‘”hello stack overflow\’s quite cool”‘ gets me far enough.
Accrding to: http://www.vias.org/linux-knowhow/bbg_sect_08_02_01.html : -r If this option is given, backslash does not act as an escape character. The backslash is considered to be part of the line. In particular, a backslash-newline pair may not be used as a line continuation. It works on my machine. $ echo ‘\&|’ | while read -r in; do … Read more
Here’s how to compare versions. using sort -V: function version_gt() { test “$(printf ‘%s\n’ “$@” | sort -V | head -n 1)” != “$1”; } example usage: first_version=5.100.2 second_version=5.1.2 if version_gt $first_version $second_version; then echo “$first_version is greater than $second_version !” fi pro: solid way to compare fancy version strings: support any length of sub-parts … Read more
Citing this source, Standard UNIX variables are split into two categories, environment variables and shell variables. In broad terms, shell variables apply only to the current instance of the shell and are used to set short-term working conditions; environment variables have a farther reaching significance, and those set at login are valid for the duration … Read more