Bash- Run multiple commands at the same time

Question

Is there a way to run multiple commands at the same time, but not moving on until both are finished? I have been trying to use similar instructions to the following, but both take a long time to complete and would be better if I could run them at the same time (cannot use & to run it on the background since the next step requires all the output files)

sed -i 's/x/y/' file1
grep 'pattern' file2 > file3

`( command )`. this launches a subshell. it's multi-processing. then you can call `wait` on both pid. have a look at a complete doc: http://tldp.org/LDP/abs/html/index.html. — Jason Hu, Jun 09 '15 at 14:54

score 3 · Answer 1 · answered Jun 09 '15 at 15:17

3

This is probably what you want:

sed -i 's/x/y/' file1 &
grep 'pattern' file2 > file3 &
wait

answered Jun 09 '15 at 15:17

twalberg

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score 1 · Answer 2 · answered Jun 09 '15 at 14:58

Not exactly the answer, but a few lines of makefile would do what you want

file1:
    sed -i 's/x/y' <someinput

file3: file2
    grep 'pattern' file2 > file3

nextop: file1 file3
    whatever you want to do next

and make -j so that tasks are done in parallel when possible

Bash- Run multiple commands at the same time

2 Answers2