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author | Tom Ryder <tom@sanctum.geek.nz> | 2017-06-02 22:07:52 +1200 |
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committer | Tom Ryder <tom@sanctum.geek.nz> | 2017-06-02 22:07:52 +1200 |
commit | bc1d5fb28841f6050605e93886685b3a02e7787a (patch) | |
tree | f0f02d8d4884b0864334ad774c98da87c0301379 /bin/chn.mi5 | |
parent | Correct some terms in man mi5(1df) (diff) | |
download | dotfiles-bc1d5fb28841f6050605e93886685b3a02e7787a.tar.gz dotfiles-bc1d5fb28841f6050605e93886685b3a02e7787a.zip |
Use mi5 to make templated shell scripts
Diffstat (limited to 'bin/chn.mi5')
-rw-r--r-- | bin/chn.mi5 | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/bin/chn.mi5 b/bin/chn.mi5 new file mode 100644 index 00000000..dfc1000c --- /dev/null +++ b/bin/chn.mi5 @@ -0,0 +1,57 @@ +# Repeat a command to filter input several times +self=chn + +# Check arguments. +if [ "$#" -lt 2 ] ; then + printf >&2 '%s: Need a count and a program name\n' "$self" + exit 2 +fi + +# Shift off the repetition count. +c=$1 +shift + +# Check the repetition count looks sane. Zero is fine! +if [ "$c" -lt 0 ] ; then + printf >&2 '%s: Nonsensical negative count\n' "$self" + exit 2 +fi + +# If the count is zero, just run the input straight through! +if [ "$c" -eq 0 ] ; then + cat + exit +fi + +<% +include(`include/mktd.m4') +%> + +# Define and create input and output files +if=$td/if of=$td/of +touch -- "$if" "$of" + +# Iterate through the count +while [ "${n=1}" -le "$c" ] ; do + + # Start a subshell so we can deal with FDs cleanly + ( + # If this isn't the first iteration, our input comes from $if + [ "$n" -eq 1 ] || + exec <"$if" + + # If this isn't the last iteration, our output goes to $of + [ "$n" -eq "$c" ] || + exec >"$of" + + # Run the command with the descriptors above; if the command fails, the + # subshell will exit, which will in turn exit the program + "$@" + ) || exit + + # Copy the output file over the input one + cp -- "$of" "$if" + + # Increment the counter for the next while loop run + n=$((n+1)) +done |